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MODULE TRIGRID

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REPLACES PANACEA module PANDORA.

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FUNCTION

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FORMAT

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COMMAND QUALIFIERS

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DESCRIPTION

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GENERAL

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TYPICAL COMMAND SEQUENCE

TRIGRID>  WINDOW 0.0 0.0 80.0 160.0! determine area of DTM
TRIGRID>  SIDELENGTH 10.0 12.0	   ! cell sidelength in X and in Y
TRIGRID>  ZLIMITS 0.0 456.0        ! overall DTM interpolation limits
TRIGRID>  TRIANGLE_LIMITS 3.0 9.0  ! individual triangle interpolation limits
TRIGRID>  FILEIN FRED		   ! read in FRED_.DTA, FRED_.NOD, and FRED_.DER
TRIGRID>  ENABLE TRACE             ! trace along original data strings for
TRIGRID>                           ! up-hill/down-hill side of line information
TRIGRID>  DATA_TYPE REAL           ! output DTM posts as real (floating point)
TRIGRID>  FILEOUT TEST3.DTI	   ! create DTI file LSL$DTI:TEST3.DTI a
TRIGRID>                           ! the output file
TRIGRID>  GO                       ! go!

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TRIGRID INPUT FILES

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TRIGRID OUTPUT FILES

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TRIGRID GRAPHICS OUTPUT OPTION

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TRIGRID COMMANDS

_@ COMMAND

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_@

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FORMAT: _@file-spec<CR>

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Command parameters:

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DESCRIPTION:

TRIGRID offers the facility of command input from an indirect command file. The '@' character preceding a file-spec will cause TRIGRID to open and read commands from the specified file until:

Nested command files are not supported (i.e. a command file containing an '@' command), although sequential '@' commands are supported when read from SYS$COMMAND.

As an aid to batch log interpretation TRIGRID will echo all commands read from an indirect command file.

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Messages:

The following messages are specific to the _@ command:

*** WARNING *** "@" must precede a file-spec

*** WARNING *** Indirect file error - returning to terminal input

*** ERROR *** Can't open indirect command file 'file-spec'

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Examples:


$ TRIGRID<CR>
DTMCREATE module TRIGRID of 16:30:12 20-NOV-87
TRIGRID> @FLOW2<CR>
TRIGRID> ENABLE DIAGNOSTICS
TRIGRID> ENABLE GRAPHICS
TRIGRID> RETURN
TRIGRID>

_! COMMAND

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_!

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FORMAT: _! [comment text]

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Command parameters:

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DESCRIPTION:

An exclamation mark is the standard DTMCREATE package comment delimiter. All text (and numbers) which lie to the right of a '!' character are excluded from command interpretation. Comments are useful for annotating command procedures used in batch processing etc_.

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Messages: None.

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Examples:


TRIGRID> _! a comment for the sake of it<CR>
TRIGRID> ENABLE GRAPHICS ! turn graphics on<CR>
TRIGRID>

DATA_TYPE COMMAND

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DATA_TYPE

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FORMAT: DATA_TYPE type

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Command parameters:

type

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DESCRIPTION:

The DATA_TYPE allows the user to specify the data type of the output DTI file which contains the DTM grid.

By default TRIGRID generates a 'MIKE' type DTI file having WORD (16 bit integer) post values.

When choosing the data type of the DTI file, consideration must be given to the Z range of the data to be output. TRIEDIT will output the DTMCREATE default null value (-32767) if data underflow or overflow occurs when writing to the DTI file.

Consideration must also be given to the nature of the output DTM. Remember that integer DTI data types (WORD and LONGWORD) quantise the Z data values. By default Z values are truncated to the next lower integer value. If the NINT option is enabled, Z values in integer DTI files are rounded to the nearest whole integer.

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Messages: None.

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Examples:


TRIGRID> DATA_TYPE REAL<CR>
TRIGRID> SHOW DATA_TYPE<CR>
DTI data type ....................................... REAL
TRIGRID>

DISABLE AUTO_LIMITS COMMAND

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DISABLE AUTO_LIMITS

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FORMAT: DISABLE AUTO_LIMITS

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Command parameters: None.

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DESCRIPTION:

DISABLE AUTO_LIMITS allows the user to cancel the effect of a previous ENABLE AUTO_LIMITS command.

When the AUTO_LIMITS option is active, TRIGRID applies interpolation limits based on the feature flag information attached to each node in the triangulation. It is then impossible, for example, for a grid height to be set below the height of a triangle vertex that is flagged as being part of a river string.

By default, the AUTO_LIMITS option is enabled during program startup.

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Messages: None.

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Examples:


TRIGRID> ENABLE AUTO_LIMITS<CR>
TRIGRID> SHOW ENABLE<CR> AUTO_LIMITS ......................................... On DIAGNOSTICS ......................................... Off GRAPHICS ............................................ Off SMOOTH .............................................. On (Smooth patch interpolation) NINT ................................................ On ORTHOGONAL .......................................... Off TRACE ............................................... Off
TRIGRID>

DISABLE DEBUG COMMAND

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DISABLE DEBUG

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FORMAT: DISABLE DEBUG

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Command parameters: None.

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DESCRIPTION:

DISABLE DEBUG allows the user to cancel the effect of a previous ENABLE DEBUG command.

When the DEBUG option is active, TRIGRID produces copious debugging information. The DEBUG option is reserved for use by Laser-Scan personnel.

By default, the DEBUG option is disabled during program startup.

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Messages: None.

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Examples:


TRIGRID> ENABLE DEBUG<CR>
TRIGRID>

DISABLE DIAGNOSTICS COMMAND

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DISABLE DIAGNOSTICS

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FORMAT: DISABLE DIAGNOSTICS

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Command parameters: None.

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DESCRIPTION:

DISABLE DIAGNOSTICS allows the user to cancel the effect of a previous ENABLE DIAGNOSTICS command.

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Messages: None.

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Examples:


TRIGRID> ENABLE DIAGNOSTICS<CR>
TRIGRID> SHOW ENABLE<CR> AUTO_LIMITS ......................................... On DIAGNOSTICS ......................................... On GRAPHICS ............................................ Off SMOOTH .............................................. On (Smooth patch interpolation) NINT ................................................ On ORTHOGONAL .......................................... Off TRACE ............................................... Off
TRIGRID>

DISABLE GRAPHICS COMMAND

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DISABLE GRAPHICS

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FORMAT: DISABLE GRAPHICS

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Command parameter: None.

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DESCRIPTION:

The DISABLE GRAPHICS command cancels the effect of a previous ENABLE GRAPHICS command.

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Messages: None.

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Examples:


$ TRIGRID<CR>
DTMCREATE module TRIGRID of 13:30:39 20-AUG-87
TRIGRID> SHOW ENABLE<CR> AUTO_LIMITS ......................................... On DIAGNOSTICS ......................................... Off GRAPHICS ............................................ Off SMOOTH .............................................. On (Smooth patch interpolation) NINT ................................................ On ORTHOGONAL .......................................... Off TRACE ............................................... Off
TRIGRID> ENABLE GRAPHICS<CR>
TRIGRID> SHOW ENABLE<CR> AUTO_LIMITS ......................................... On DIAGNOSTICS ......................................... Off GRAPHICS ............................................ On SMOOTH .............................................. On (Smooth patch interpolation) NINT ................................................ On ORTHOGONAL .......................................... Off TRACE ............................................... Off
TRIGRID> DISABLE GRAPHICS<CR>
TRIGRID> SHOW ENABLE<CR> AUTO_LIMITS ......................................... On DIAGNOSTICS ......................................... Off GRAPHICS ............................................ Off SMOOTH .............................................. On (Smooth patch interpolation) NINT ................................................ On ORTHOGONAL .......................................... Off TRACE ............................................... Off
TRIGRID>

DISABLE NINT COMMAND

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DISABLE NINT

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FORMAT: DISABLE NINT

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Command parameters: None.

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DESCRIPTION:

DISABLE NINT allows the user to cancel the effect of a previous ENABLE NINT command.

When output is directed to a word or longword DTI file it is necessary to convert the real height value interpolated within TRIGRID to an integer value. This conversion is normally done using the FORTRAN NINT intrinsic function (round to nearest integer). However, some customers prefer to use integer truncation (FORTRAN INT intrinsic function).

The ENABLE NINT and DISABLE NINT commands allow the user to specify which of these two functions is to be used, i.e.


	ENABLE NINT - use NINT, round to nearest integer value (Default) 
	DISABLE NINT - use INT, truncate to integer value

By default, the NINT option is enabled during program startup.

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Messages: None.

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Examples:


TRIGRID> ENABLE NINT<CR>
TRIGRID> SHOW ENABLE<CR> AUTO_LIMITS ......................................... On DIAGNOSTICS ......................................... Off GRAPHICS ............................................ Off SMOOTH .............................................. On (Smooth patch interpolation) NINT ................................................ On ORTHOGONAL .......................................... Off TRACE ............................................... Off
TRIGRID>

DISABLE ORTHOGONAL COMMAND

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DISABLE ORTHOGONAL

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FORMAT: DISABLE ORTHOGONAL

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Command parameters: None.

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DESCRIPTION:

DISABLE ORTHOGONAL allows the user to cancel the effect of a previous ENABLE ORTHOGONAL command.

When the ORTHOGONAL option is active, individual triangle interpolation under-shoot and over-shoot limits are applied orthogonal to the triangle facet plane. The default action is to apply the limits vertically regardless of the slope of the triangle facet plane. ENABLE ORTHOGONAL is not recommended for use with data sets which have regularly spaced contours of regular interval but will be beneficial if the contour data have an irregular interval and have irregular spacing.

By default, the ORTHOGONAL option is disabled during program startup.

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Messages: None.

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Examples:


TRIGRID> ENABLE ORTHOGONAL<CR>
TRIGRID> SHOW ENABLE<CR> AUTO_LIMITS ......................................... On DIAGNOSTICS ......................................... Off GRAPHICS ............................................ Off SMOOTH .............................................. On (Smooth patch interpolation) NINT ................................................ On ORTHOGONAL .......................................... Off TRACE ............................................... Off
TRIGRID>

DISABLE PME COMMAND

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DISABLE PME

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FORMAT: DISABLE PME

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Command parameters: None.

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DESCRIPTION:

The ENABLE PME and DISABLE PME commands are reserved for Laser-Scan use. PME is a code optimisation tool and should be invoked by LSL software personnel only.

DISABLE PME disables the effect of a previous ENABLE PME command and causes the PME_EXIT routine to be invoked.

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Message:

The following warning message is specific to the DISABLE PME command:

*** WARNING *** You were not using PME anyway!

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Examples:


$ TRIGRID<CR>
DTMCREATE module TRIGRID of 13:30:39 20-AUG-87
TRIGRID> ENABLE PME ! turn PME on<CR>
TRIGRID> DISABLE PME ! turn it off again!!<CR>
TRIGRID>

DISABLE SMOOTH COMMAND

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DISABLE SMOOTH

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FORMAT: DISABLE SMOOTH

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Command parameters: None.

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DESCRIPTION:

DISABLE SMOOTH allows the user to cancel the effect of a previous ENABLE SMOOTH command.

By default, the SMOOTH option is enabled during program startup.

The DISABLE SMOOTH command disables grid point estimation by smooth patches. Grid heights are instead estimated using linear interpolation across the triangle facet planes. Smooth patch estimation tends to give a more rounded smooth appearance to a DTM surface than that given by linear facets.

If smooth patch interpolation is selected, individual triangle interpolation limits are applied. Linear facet interpolation, by definition, does not need to apply interpolation limits as interpolation is restricted to the triangle facet plane.

For further details of interpolation limits, see the LIMITS, TRIANGLE_LIMITS and ENABLE AUTO_LIMITS commands.

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Messages:

The following messages are specific to the DISABLE SMOOTH command:


*** WARNING *** Linear facet interpolation selected. No smooth patch
                interpolation limits will be applied
                and the ENABLE TRACE command will be ignored

*** WARNING *** Linear facet interpolation selected.
                The ENABLE TRACE command and any smooth patch
                interpolation will be ignored

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Examples:


TRIGRID> DISABLE SMOOTH<CR>

*** WARNING *** Linear facet interpolation selected.
                The ENABLE TRACE command and any smooth patch
                interpolation will be ignored


TRIGRID>

DISABLE TRACE COMMAND

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DISABLE TRACE

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FORMAT: DISABLE TRACE

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Command parameters: None.

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DESCRIPTION:

DISABLE TRACE allows the user to cancel the effect of a previous ENABLE TRACE command.

The TRACE option causes TRIGRID to calculate up-hill/down-hill side of line context for the original data strings input to (and optionally constrained) in TRIANG. These up-hill/down-hill data are then used to apply further interpolation limits to each individual triangle. These additional limits ensure that triangles whose vertices indicate a flat plane do bulge in the correct direction relative to surrounding hill slopes even when the slope derivatives estimated for the triangle vertices conflict due to complex surrounding relief.

It is strongly recommended that the trace option is selected, particularly if the resulting DTM is to be re-contoured.

By default, the TRACE option is disabled during program startup.

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Messages: None.

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Examples:


TRIGRID> ENABLE TRACE<CR>
TRIGRID> SHOW ENABLE<CR> AUTO_LIMITS ......................................... On DIAGNOSTICS ......................................... Off GRAPHICS ............................................ Off SMOOTH .............................................. On (Smooth patch interpolation) NINT ................................................ On ORTHOGONAL .......................................... Off TRACE ............................................... Off
TRIGRID>

ENABLE AUTO_LIMITS COMMAND

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ENABLE AUTO_LIMITS

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FORMAT: ENABLE AUTO_LIMITS --------------------------------------------------------------------------------
Command parameters: None.

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DESCRIPTION:

ENABLE AUTO_LIMITS enables the user to activate the application of automatic limits to grid interpolation.

When the AUTO_LIMITS option is active, TRIGRID applies interpolation limits based on the feature flag information attached to each node in the triangulation. It is then impossible, for example, for a grid height to be set below the height of a triangle vertex that is flagged as being part of a river string.

By default, the AUTO_LIMITS option is enabled during program startup.

The AUTO_LIMITS option may be cancelled by the DISABLE AUTO_LIMITS command.

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Messages: None.

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Examples:


TRIGRID> ENABLE AUTO_LIMITS<CR>
TRIGRID>

ENABLE DEBUG COMMAND

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ENABLE DEBUG

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FORMAT: ENABLE DEBUG

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Command parameters: None.

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DESCRIPTION:

When the DEBUG option is active, TRIGRID produces copious debugging information. The DEBUG option is reserved for use by Laser-Scan personnel.

By default, the DEBUG option is disabled during program startup.

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Messages: None.

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Examples:


TRIGRID> ENABLE DEBUG<CR>
TRIGRID>

ENABLE DIAGNOSTICS COMMAND

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ENABLE DIAGNOSTICS

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FORMAT: ENABLE DIAGNOSTICS

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Command parameters: None.

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DESCRIPTION:

ENABLE DIAGNOSTICS allows the user to enable diagnostic printout.

Because it is usually used in a batch processing environment, by default TRIGRID produces minimal diagnostic printout. If however, the user wishes to receive indications of processing progress and of the effect of selections on data input, diagnostic printout may be selected with the ENABLE DIAGNOSTICS command.

On a heavily loaded computer it may be reassuring to ENABLE DIAGNOSTICS to indicate progress through the data set. If SYS$OUTPUT is directed to a video screen terminal, messages indicating percentage progress are issued.

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Messages: None.

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Examples:


TRIGRID> ENABLE DIAGNOSTICS<CR>
TRIGRID> SHOW ENABLE<CR> AUTO_LIMITS ......................................... On DIAGNOSTICS ......................................... On GRAPHICS ............................................ Off SMOOTH .............................................. On (Smooth patch interpolation) NINT ................................................ On ORTHOGONAL .......................................... Off TRACE ............................................... Off
TRIGRID>

ENABLE GRAPHICS COMMAND

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ENABLE GRAPHICS

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FORMAT: ENABLE GRAPHICS

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Command parameters: None.

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DESCRIPTION:

TRIGRID offers the option to generate graphic output to indicate processing progress. By default graphic output is disabled. To prevent a user selecting graphics when it is inappropriate to the current terminal, TRIGRID uses a lookup table of terminal characteristics associated with all available terminal lines (see Appendix 1). An invalid graphics selection will result in a warning message and the GRAPHICS option being deselected.

Graphics selection may be cancelled with the DISABLE GRAPHICS command.

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Messages:

The following messages are specific to the ENABLE GRAPHICS command:

*** ERROR  *** reading lookup file at line 'integer'
*** WARNING *** Unable to open "LSL$LOOKUP:TERMTYPE.DAT"
Sorry 'name' terminal  'terminal-ident' isn't in the lookup table
Sorry 'name' terminal 'terminal-ident' can't support graphics
*** ERROR  *** translating logical name LSL$DTMCREATETERMINAL

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Examples:


$ TRIGRID<CR>
DTMCREATE module TRIGRID of 13:30:39 20-AUG-87
TRIGRID> ENABLE GRAPHICS<CR>
TRIGRID>

ENABLE NINT COMMAND

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ENABLE NINT

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FORMAT: ENABLE NINT

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Command parameters: None.

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DESCRIPTION:

When output is directed to a word or longword DTI file it is necessary to convert the real height value interpolated within TRIGRID to an integer value. This conversion is normally done using the FORTRAN NINT intrinsic function (round to nearest integer). However, some customers prefer to use integer truncation (FORTRAN INT intrinsic function).

The ENABLE NINT and DISABLE NINT commands allow the user to specify which of these two functions is to be used, i.e.


	ENABLE NINT - use NINT, round to nearest integer value (Default) 
	DISABLE NINT - use INT, truncate to integer value

By default, the NINT option is enabled during program startup.

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Messages: None.

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Examples:


TRIGRID> ENABLE NINT<CR>
TRIGRID> SHOW ENABLE<CR> AUTO_LIMITS ......................................... On DIAGNOSTICS ......................................... Off GRAPHICS ............................................ Off SMOOTH .............................................. On (Smooth patch interpolation) NINT ................................................ On ORTHOGONAL .......................................... Off TRACE ............................................... Off
TRIGRID>

ENABLE ORTHOGONAL COMMAND

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ENABLE ORTHOGONAL

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FORMAT: ENABLE ORTHOGONAL

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Command parameters: None.

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DESCRIPTION:

When the ORTHOGONAL option is active, individual triangle interpolation under-shoot and over-shoot limits are applied orthogonal to the triangle facet plane. The default action is to apply the limits vertically regardless of the slope of the triangle facet plane. ENABLE ORTHOGONAL is not recommended for use with data sets which have regularly spaced contours of regular interval but will be beneficial if the contour data have an irregular interval and have irregular spacing.

The effect of an ENABLE ORTHOGONAL command may be cancelled with a DISABLE ORTHOGONAL command.

By default, the ORTHOGONAL option is disabled during program startup.

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Messages: None.

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Examples:


TRIGRID> ENABLE ORTHOGONAL<CR>
TRIGRID> SHOW ENABLE<CR> AUTO_LIMITS ......................................... On DIAGNOSTICS ......................................... Off GRAPHICS ............................................ Off SMOOTH .............................................. On (Smooth patch interpolation) NINT ................................................ On ORTHOGONAL .......................................... On TRACE ............................................... Off
TRIGRID>

ENABLE PME COMMAND

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ENABLE PME

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FORMAT: ENABLE PME

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Command parameters: None.

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DESCRIPTION:

The ENABLE PME and DISABLE PME commands are reserved for Laser-Scan use. PME is a code optimisation tool and should be invoked by LSL software personnel only.

ENABLE PME causes the PME_INIT routine to be invoked.

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Message:

The following warning message is specific to the ENABLE PME command:

*** WARNING *** You are already using PME!

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Examples:


$ TRIGRID<CR>
DTMCREATE module TRIGRID of 13:30:39 20-AUG-87
TRIGRID> ENABLE PME<CR>
TRIGRID> FILEIN DUA3:[DEMONSTRATION]IDAHO<CR>
_.DTA file DUA3:[DEMONSTRATION]IDAHO_.DTA;15 opened for read
_.NOD file DUA3:[DEMONSTRATION]IDAHO_.NOD;15 opened for read
_.DER file DUA3:[DEMONSTRATION]IDAHO_.DER;15 opened for read
TRIGRID>

ENABLE SMOOTH COMMAND

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ENABLE SMOOTH

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FORMAT: ENABLE SMOOTH

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Command parameters: None.

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DESCRIPTION:

The ENABLE SMOOTH command enables grid point estimation by smooth patches. Smooth patch estimation tends to give a more rounded smooth appearance to a DTM surface than that given by linear facets.

By default, the SMOOTH option is enabled during program startup.

If smooth patch interpolation is selected, individual triangle interpolation limits are applied. Linear facet interpolation, by definition, does not need to apply interpolation limits as interpolation is restricted to the triangle facet plane.

The DISABLE SMOOTH command disables grid point estimation by smooth patches. Grid heights are instead estimated using linear interpolation across the triangle facet planes.

For further details of interpolation limits, see the LIMITS, TRIANGLE_LIMITS and ENABLE AUTO_LIMITS commands.

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Messages: None.

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Examples:


TRIGRID> ENABLE SMOOTH<CR>
TRIGRID>

ENABLE TRACE COMMAND

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ENABLE TRACE

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FORMAT: ENABLE TRACE

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Command parameters: None.

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DESCRIPTION:

The TRACE option causes TRIGRID to calculate up-hill/down-hill side of line context for the original data strings input to (and optionally constrained) in TRIANG. These up-hill/down-hill data are then used to apply further interpolation limits to each individual triangle. These additional limits ensure that triangles whose vertices indicate a flat plane do bulge in the correct direction relative to surrounding hill slopes even when the slope derivatives estimated for the triangle vertices conflict due to complex surrounding relief.

It is strongly recommended that the trace option is selected, particularly if the resulting DTM is to be re-contoured.

By default, the TRACE option is disabled during program startup.

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Messages: None.

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Examples:


TRIGRID> ENABLE TRACE<CR>
TRIGRID>

FILEIN COMMAND

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FILEIN

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FORMAT: FILEIN file-spec

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COMMAND PARAMETERS:

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DESCRIPTION:

TRIGRID expects as input the 2 binary structured data files (the matched pair of _.NOD and _.DTA files) produced by TRIANG or TRIEDIT, and the _.DER file containing the slope derivatives estimated by TRIDER.

The TRIGRID input file specification is used as a generic file-spec for all three input (_.NOD, _.DTA and _.DER) files.

Any parts missing from the generic file-specification are taken from the from the defaults SYS$DISK:[]_.DTA;0 and SYS$DISK:[]_.NOD;0.

Since it is essential that the file version numbers of the _.NOD, _.DTA and _.DER file always match, TRIGRID performs checks on file version numbers. If mismatches are found, TRIGRID complains and aborts execution.

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Messages:

The following messages are specific to the FILEIN command:

*** WARNING *** You must specify a file-spec argument to the FILEIN command
For example FILEIN SWAREA_.DTA

*** ERROR *** Unable to interpret input file-spec

*** ERROR *** opening input file

_.DTA file 'file-spec' opened for read
_.NOD file 'file-spec' opened for read
_.DER file 'file-spec' opened for read

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Examples:


TRIGRID> FILEIN DUA3:[DEMONSTRATION]IDAHO<CR>
_.DTA file DUA3:[DEMONSTRATION]IDAHO_.DTA;15 opened for read
_.NOD file DUA3:[DEMONSTRATION]IDAHO_.NOD;15 opened for read
_.DER file DUA3:[DEMONSTRATION]IDAHO_.DER;15 opened for read
TRIGRID>

FILEOUT COMMAND

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FILEOUT

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FORMAT: FILEOUT file-spec

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COMMAND PARAMETERS:

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DESCRIPTION:

The FILEOUT command is used to specify the DTI file which is to be created and opened for data output.

The DTI file is not actually created and opened until a GO command is accepted, as the user may redefine the DTI header type (HEADER_TYPE command) or the DTI data type (DATA_TYPE command) after issuing the FILEOUT command.

By default TRIGRID creates a DTI file having an LSLA type header and word data type.

The characteristics of the output DTI file are determined by the HEADER_TYPE and DATA_TYPE commands, and its size by combinations of WINDOW, SIZE or SIDELENGTH commands.

If a set type 2 IFF MD (Map Descriptor) or a set DTI file projection record were available in the first file read into TRIANG using a FILEIN command, TRIANG puts this information into the _.NOD and _.DTA files. If TRIGRID is creating a DTI file with an LSLA type header this projection information is copied from the _.DTA amd _.NOD files into the TRIGRID DTI file header after appropriate modifications of extent, origin and gridstep.

In contrast, it is left to the user to set DTED DTI file header contents using DTEDIFF and MCEHED.

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Messages:

The following messages are specific to the FILEOUT command:

*** WARNING *** You must specify a file-spec argument to the FILEOUT command
For example FILEOUT SWAREA_.DTI

*** ERROR *** Unable to interpret input file-spec

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Examples:


TRIGRID> FILEOUT IDAHO<CR>
TRIGRID>

GO COMMAND

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GO

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FORMAT: GO

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Command parameters: None.

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DESCRIPTION:

When all necessary files have been read in the GO command will cause the DTI file specified with the FILEOUT command to be created and opened. TRIGRID will then commence the gridding process. Unless relatively small data-sets are being handled (say less then 50,000 data points) it is strongly recommended that TRIGRID is run in batch mode at an off-peak time.

When grid creation is complete, TRIGRID closes the output DTI file and then exits.

Before the GO command will be accepted, TRIGRID performs checks that the following obligatory commands have been issued:


                1) WINDOW
                2) SIZE (or SIDELENGTH)
                3) FILEIN
                4) FILEOUT

If one (or more) of these commands has not yet been issued and accepted, TRIGRID will ignore the GO command and prompt for further commands at the terminal. The SHOW ENABLE command can be used to discover the current command option settings.

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Messages:

*** WARNING *** The following commands must be given
                before processing can begin:
                1) WINDOW
                2) SIZE (or SIDELENGTH)
                3) FILEIN
                4) FILEOUT

Once the GO command has been accepted no more conversational messages of the *** WARNING *** format will be issued. Any messages will relate to serious processing problems and will normally result in abnormal TRIGRID termination. The messages relating to non-interactive processing problems are presented at the end of this document.

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Examples:


TRIGRID> GO<CR> DTI file LSL$DTI:TEST_DTM.DTI opened for write File : LSL$DTI:TEST_DTM.DTI Header : LSLA Data: WORD Units are Metres Matrix Coverage SW: 0.00 0.00 NE: 200.00 199.50 Matrix Interval E: 2.00 N: 1.50 Value Range : 0 to 0

ELAPSED: 0 00:05:21.82 CPU: 0:00:01.40 BUFIO: 51 DIRIO: 15 FAULTS: 170
$

HEADER_TYPE COMMAND

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HEADER_TYPE

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FORMAT: HEADER_TYPE type

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Command parameters:

type

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DESCRIPTION:

The HEADER_TYPE allows the user to specify the header type of the output DTI file which contains the DTM grid.

By default TRIGRID generates a 'LSLA' type DTI file having WORD (16 bit integer) post values.

For a detailed description of the layout and content of DTI file header types see the DTILIB section of the MATRIX Reference Manual.

The default LSLA type DTI header contains only the matrix X and Y extent, Z range and the X and Y grid interval.

Due to the general purpose nature of TRIGRID it is not possible to collect from the user, and validate, all the complex information required to complete a military TED4 or UHL1 DTI header. Instead TRIGRID puts into a TED4 or UHL1 header the same information as for a LSLA type DTI. If output is to a TED4 type DTI file, the Latitude and Longitude origin and the Latitude and Longitude bounding rectangle values are inserted into the DSI record. These values are taken from the WINDOW command arguments. It is assumed that the triangulation units are tenths of seconds of arc.

The user is left to use the MATRIX package utility DTIPATCH to set up missing information.

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Messages: None.

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Examples:


TRIGRID> HEADER_TYPE TED4<CR>
TRIGRID>

HELP COMMAND

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HELP

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FORMAT: HELP subject

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Command parameters:

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Description:

The HELP command looks the rest of the line up in the DTMCREATE HELP library. This library contains a brief summary of the operation of each command.

The information is looked up in the TRIGRID section of the DTMCREATE help library, LSL$HELP:DTMCREATE.HLB.

--------------------------------------------------------------------------------
Messages:

Where required, warning messages are output via the VMS LBR$OUTPUT_HELP utility.

--------------------------------------------------------------------------------
Examples:


TRIGRID> HELP RETURN<CR>

RETURN

TRIGRID>

PAUSE COMMAND

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PAUSE

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FORMAT: PAUSE

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Command parameters: None.

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DESCRIPTION:

Pauses TRIGRID execution and issues a prompt for a carriage return to continue execution. This command is designed for use in software demonstration situations.

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Messages: None.

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Examples:


TRIGRID> PAUSE<CR>


Press to continue<CR>
TRIGRID>

QUIT COMMAND

--------------------------------------------------------------------------------
QUIT

--------------------------------------------------------------------------------
FORMAT: QUIT

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Command parameters: None.

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Description:

The QUIT command causes TRIGRID to exit immediately, closing all input files and closing and deleting all output files.

(pressing the Ctrl and Z keys together) may also be used to quit from the program.

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Messages: None.

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Examples:

TRIGRID> QUIT<CR>
ELAPSED: 00:05:25.84 CPU: 0:00:05.71 BUFIO: 281 DIRIO: 46 FAULTS: 263
_$

RETURN COMMAND

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RETURN

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FORMAT: RETURN

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Command parameters: None.

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DESCRIPTION:

Restores command input from an indirect file to SYS$COMMAND.

A typical application is to allow the user to use an indirect command file to set up those run time defaults which are constant within a flowline and then return to input from the terminal (or batch stream) for the run specific commands. To do this RETURN must be the last command in the indirect command file.

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Messages:

The following messages are specific to the RETURN command:

RETURN command detected - returning to terminal input

RETURN command ignored - command input is already from terminal

--------------------------------------------------------------------------------
Examples:


TRIGRID> @FLOW2<CR>
TRIGRID> ENABLE DIAGNOSTICS
TRIGRID> RETURN
TRIGRID>

SHOW COMMAND

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SHOW

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FORMAT: SHOW subject

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Command parameters:

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DESCRIPTION:

SHOW command enables the user to examine the current status of TRIGRID options and parameter settings.

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Messages:

TRIGRID issues the following message if the SHOW command is specified without an argument:


*** ERROR *** Specifying command SHOW

Available SHOW command qualifiers are:

DATA_TYPE    ENABLE       FILES    HEADER_TYPE     LIMITS     SIDELENGTH

SIZE         UNITS        WINDOW

This feature can be used to advantage if the user wishes to quickly determine for which items the SHOW facility is available.

--------------------------------------------------------------------------------
Examples:

$ TRIGRID<CR>

DTMCREATE module TRIGRID of 14:02:31 3-FEB-89
TRIGRID> SHOW<CR>

*** ERROR *** Specifying command SHOW

Available SHOW command qualifiers are:

DATA_TYPE    ENABLE       FILES    HEADER_TYPE     LIMITS     SIDELENGTH

SIZE         UNITS        WINDOW


TRIGRID> SHOW ENABLE ! examine current option settings<CR> AUTO_LIMITS ......................................... On DIAGNOSTICS ......................................... Off GRAPHICS ............................................ Off SMOOTH .............................................. On (Smooth patch interpolation) NINT ................................................ On ORTHOGONAL .......................................... Off TRACE ............................................... Off
TRIGRID>

SHOW DATA_TYPE COMMAND

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SHOW DATA_TYPE

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FORMAT: SHOW DATA_TYPE

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Command parameters: None.

--------------------------------------------------------------------------------
DESCRIPTION:

SHOW DATA_TYPE enables the user to examine the current setting for the DATA_TYPE command. This determines the data type of the output DTI file.

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Messages: None.

--------------------------------------------------------------------------------
Examples:

$ TRIGRID<CR>
DTMCREATE module TRIGRID of 17:02:12 23-JAN-89

TRIGRID> SHOW DATA_TYPE ! examine current data_type settings<CR>
DTI data type ....................................... WORD
TRIGRID>

SHOW ENABLE COMMAND

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SHOW ENABLE

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FORMAT: SHOW ENABLE

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Command parameters: None.

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DESCRIPTION:

SHOW ENABLE enables the user to examine the current status of TRIGRID processing options that are set or unset using the ENABLE and DISABLE commands.

--------------------------------------------------------------------------------
Messages: None.

--------------------------------------------------------------------------------
Examples:

$ TRIGRID<CR>
DTMCREATE module TRIGRID of 17:02:12 23-JAN-89

TRIGRID> SHOW ENABLE ! examine current option settings<CR>
TRIGRID>

SHOW FILES COMMAND

--------------------------------------------------------------------------------
SHOW FILES

--------------------------------------------------------------------------------
FORMAT: SHOW FILES

--------------------------------------------------------------------------------
Command parameters: None.

--------------------------------------------------------------------------------
DESCRIPTION:

SHOW FILES enables the user to examine the current status of TRIGRID input files.

--------------------------------------------------------------------------------
Messages: None.

--------------------------------------------------------------------------------
Examples:

$ TRIGRID<CR>
DTMCREATE module TRIGRID of 17:02:12 23-JAN-89

TRIGRID> SHOW FILES ! examine files<CR> Input files: The input files are undefined Output file: The DTI output file is undefined
TRIGRID> FILEOUT EXAMPLE ! open output DTI file<CR>
TRIGRID> SHOW FILES ! examine input file-specs<CR> Input files: The input files are undefined Output file: LSL$DATA_ROOT:[LSL.DTI]EXAMPLE.DTI;0 (DTI file window or size are currently undefined)
TRIGRID> FILEIN SW100230 ! get input files<CR>
_.DTA file DUA3:[DEMONSTRATION]SW100230_.DTA;6 opened for read
_.NOD file DUA3:[DEMONSTRATION]SW100230_.NOD;6 opened for read
_.DER file DUA3:[DEMONSTRATION]SW100230_.DER;6 opened for read
TRIGRID> SHOW FILES ! examine input file-specs<CR> Input files:
_.DTA file: DUA3:[DEMONSTRATION]SW100230_.DTA;6
_.NOD file: DUA3:[DEMONSTRATION]SW100230_.NOD;6
_.DER file: DUA3:[DEMONSTRATION]SW100230_.DER;6 Output file: LSL$DATA_ROOT:[LSL.DTI]EXAMPLE.DTI;0 (DTI file window or size are currently undefined)
TRIGRID>

SHOW HEADER_TYPE COMMAND

--------------------------------------------------------------------------------
SHOW HEADER_TYPE

--------------------------------------------------------------------------------
FORMAT: SHOW HEADER_TYPE

--------------------------------------------------------------------------------
Command parameters: None.

--------------------------------------------------------------------------------
DESCRIPTION:

SHOW HEADER_TYPE enables the user to examine the current setting for the HEADER_TYPE command. This determines the header type of the output DTI file.

--------------------------------------------------------------------------------
Messages: None.

--------------------------------------------------------------------------------
Examples:

$ TRIGRID<CR>
DTMCREATE module TRIGRID of 17:02:12 23-JAN-89

TRIGRID> SHOW HEADER_TYPE ! examine current data_type settings<CR>
DTI header type ...................................... LSLA
TRIGRID>

SHOW LIMITS COMMAND

--------------------------------------------------------------------------------
SHOW LIMITS

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FORMAT: SHOW LIMITS

--------------------------------------------------------------------------------
Command parameters: None.

--------------------------------------------------------------------------------
DESCRIPTION:

SHOW LIMITS enables the user to examine the current status of TRIGRID Z-limits parameters set using the LIMITS commands.

--------------------------------------------------------------------------------
Messages: None.

--------------------------------------------------------------------------------
Examples:

$ TRIGRID<CR>
DTMCREATE module TRIGRID of 17:02:12 23-JAN-89

TRIGRID> SHOW LIMITS ! examine LIMITS settings<CR>
No individual triangle interpolation limits will be applied
No whole DTM Z-limits will be applied
TRIGRID>

SHOW SIDELENGTH COMMAND

--------------------------------------------------------------------------------
SHOW SIDELENGTH

--------------------------------------------------------------------------------
FORMAT: SHOW SIDELENGTH

--------------------------------------------------------------------------------
Command parameters: None.

--------------------------------------------------------------------------------
DESCRIPTION:

SHOW SIDELENGTH enables the user to examine the current status of TRIGRID DTI file sidelength parameters set using the SIDELENGTH or the combination of SIZE and WINDOW commands.

--------------------------------------------------------------------------------
Messages: None.

--------------------------------------------------------------------------------
Examples:

$ TRIGRID<CR>
DTMCREATE module TRIGRID of 17:02:12 23-JAN-89

TRIGRID> SHOW SIDELENGTH ! examine sidelength settings<CR> X-sidelength ........................................ Unset Y-sidelength ........................................ Unset
TRIGRID> SIDELENGTH 4.0 4.0 ! set x and y sidelength <CR>
TRIGRID> SHOW SIDELENGTH ! examine sidelength settings<CR> X-sidelength ........................................ 4.0 Y-sidelength ........................................ 4.0
TRIGRID>

SHOW SIZE COMMAND

--------------------------------------------------------------------------------
SHOW SIZE

--------------------------------------------------------------------------------
FORMAT: SHOW SIZE

--------------------------------------------------------------------------------
Command parameters: None.

--------------------------------------------------------------------------------
DESCRIPTION:

SHOW SIZE enables the user to examine the current status of TRIGRID output DTI file SIZE parameters set using the SIZE or the combination of SIDELENGTH and WINDOW commands.

--------------------------------------------------------------------------------
Messages: None.

--------------------------------------------------------------------------------
Examples:

$ TRIGRID<CR>
DTMCREATE module TRIGRID of 17:02:12 23-JAN-89

TRIGRID> SHOW SIZE ! examine size settings<CR>
Number of columns ................................... Unset
Number of rows ...................................... Unset
TRIGRID> SIZE 801 401 ! set x and y sidelength <CR>
TRIGRID> SHOW SIZE ! examine sidelength settings<CR>
Number of columns ................................... 801
Number of rows ...................................... 401
TRIGRID>

SHOW UNITS COMMAND

--------------------------------------------------------------------------------
SHOW UNITS

--------------------------------------------------------------------------------
FORMAT: SHOW UNITS

--------------------------------------------------------------------------------
Command parameters: None.

--------------------------------------------------------------------------------
DESCRIPTION:

Shows current status of TRIGRID window units as set using the UNITS command.

--------------------------------------------------------------------------------
Messages: None.

--------------------------------------------------------------------------------
Examples:

_$ TRIGRID<CR>
DTMCREATE module TRIGRID of 13:53:27  3-FEB-89
TRIGRID> SHOW UNITS<CR>
Window to be specified in metres

TRIGRID>

SHOW WINDOW COMMAND

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SHOW WINDOW

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FORMAT: SHOW WINDOW

--------------------------------------------------------------------------------
Command parameters: None.

--------------------------------------------------------------------------------
DESCRIPTION:

Shows current triangulation and DTM window values.

The units of the WINDOW command parameters are set using the UNITS command. By default metre units are assumed. If it is more convenient to specify the window in latitude and longitude the sexagesimal lat long values may be supplied after specifying a UNITS LATLONG command. This assumes that the data read in from the DTI and IFF files uaing TRIANG were in units of tenths second of arc. A similar assumption is made for UNITS SECONDS.

The SHOW WINDOW command displays the window values in the units currently selected by the UNITS command. No projection transformation is performed, so the unwise user could easily specify that the window be shown as latitude longitude despite the fact that his data are in metres!

--------------------------------------------------------------------------------
Messages: None.

--------------------------------------------------------------------------------
Examples:

_$ TRIGRID<CR> DTMCREATE module TRIGRID of 13:53:27 3-FEB-89 TRIGRID> SHOW WINDOW<CR> Window units are metres DTM WINDOW currently undefined Triangulation coverage currently unknown
TRIGRID>

SIDELENGTH COMMAND

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SIDELENGTH

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FORMAT: SIDELENGTH x-sidelength y-sidelength

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Command parameters:

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DESCRIPTION:

The SIDELENGTH command enables the user to specify the spacing between the columns and rows of the output DTM. The SIDELENGTH command arguments should be specified in the units used for the triangulation.

If a SIZE command has already been issued then the SIZE values will be overridden by new size values calculated when WINDOW is set using:


        NUMBER OF COLUMNS = X WINDOW LENGTH/ X_SIDELENGTH +1.5

        NUMBER OF ROWS    = Y WINDOW LENGTH/ Y_SIDELENGTH +1.5

and the message:

Over-riding SIZE settings


will appear.

If the WINDOW is set, the number of rows and columns to cover completely (possibly with some overlap) the specified area is calculated. The results of this calculation will be displayed:


Window units are metres

Triangulation coverage SW:  'real' 'real' NE:  'real' 'real'
Triangulation window   SW:  'real' 'real' NE:  'real' 'real'

Which with a side length of    10.00 in X and     10.00 in Y
gives 'integer' rows and 'integer' columns in the dtm

You may use the SIDELENGTH and WINDOW commands in combination as often as you wish until the desired model characteristics are achieved.

--------------------------------------------------------------------------------
Messages:

The following messages are specific to the SIDELENGTH command:

*** WARNING *** You must have at least 3 rows and 3 columns in your DTM

*** WARNING *** You must specify at least one argument

--------------------------------------------------------------------------------
Examples:


TRIGRID> SIDELENGTH 40.0 50.0<CR>
TRIGRID>

SIZE COMMAND

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SIZE

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FORMAT: SIZE ncols nrows

--------------------------------------------------------------------------------
Command parameters:

--------------------------------------------------------------------------------
DESCRIPTION:

The SIZE command enables the user to explicitly set the number of columns and rows in the output DTM.

If you have already issued a SIDELENGTH command then the sidelength values that you specified will be replaced by the values calculated from WINDOW divided by the number of rows and number of columns and the message:

Over-riding SIDELENGTH settings


will appear.

If you have already specified values for the WINDOW then TRIGRID will calculate the cell sidelength required to give you the the number of rows and columns specified by the SIZE command and the results of this calculation will be displayed:


Window units are metres

Triangulation coverage SW:  'real' 'real' NE:  'real' 'real'
Triangulation window   SW:  'real' 'real' NE:  'real' 'real'

Which with a side length of    10.00 in X and     10.00 in Y
gives 'integer' rows and 'integer' columns in the dtm

You may use the SIZE and WINDOW commands in combination as often as you wish until the desired model characteristics are achieved.

--------------------------------------------------------------------------------
Messages:

The following messages are specific to the SIZE command:

*** WARNING *** You must have at least 3 rows and 3 columns in your DTM

*** WARNING *** You must specify at least one argument

--------------------------------------------------------------------------------
Examples:


TRIGRID> SIZE 101 201<CR>
TRIGRID>

SPAWN COMMAND

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SPAWN

--------------------------------------------------------------------------------
FORMAT: SPAWN command-line

--------------------------------------------------------------------------------
Command parameters:

--------------------------------------------------------------------------------
DESCRIPTION:

The SPAWN command enables you to create a subprocess while within TRIGRID. When the subprocess terminates control is returned to TRIGRID.

--------------------------------------------------------------------------------
Messages:

The following warning messages are specific to the SPAWN command:

*** WARNING *** SPAWN requires a valid DCL command line

*** ERROR *** Unable to spawn command, returning to TRIGRID

--------------------------------------------------------------------------------
Examples:


TRIGRID> SPAWN DIRECTORY *_.DTA;*<CR>

Directory DUA3:[DTMCREATE.ACCEPTANCE_TESTS]
TEST1_.DTA;1              8/8       18-AUG-1987 07:56  [LSL,TIM]
TEST2_.DTA;2              7/8       18-AUG-1987 17:17  [LSL,TIM]
TEST2_.DTA;1              7/8       18-AUG-1987 17:07  [LSL,TIM]
Total of 3 files, 22/24 blocks.

TRIGRID>

TRIANGLE_LIMITS COMMAND

--------------------------------------------------------------------------------
TRIANGLE_LIMITS

--------------------------------------------------------------------------------
FORMAT: TRIANGLE_LIMITS real1 real2

--------------------------------------------------------------------------------
COMMAND PARAMETERS:

--------------------------------------------------------------------------------
Description:

By default TRIGRID applies no limits to post height estimation.

The undershoot and overshoot limits for individual triangles define how far an interpolation within the triangle may fall below or above the range of heights given by the values at the vertices of the triangle. These undershoot and overshoot limits are automatically modified by the ENABLE AUTO_LIMITS command when appropriate node feature flags are detected. For example, a triangle which has one or more nodes flagged as "river" nodes will be allowed no interpolation undershoot at all.

No triangle limits are applied if the linear facet interpolation option is selected as the interpolation is restricted to the triangle facet plane itself. The same effect can be achieved (rather extravagantly) by setting both the undershoot and overshoot triangle limits to 0.0 and then using the SMOOTH patch interpolation option!

--------------------------------------------------------------------------------
Messages:

The following messages are specific to the TRIANGLE_LIMITS command:

*** WARNING *** You must specify lower and upper limit arguments
Lower limit, upper limit?

--------------------------------------------------------------------------------
Examples:


TRIGRID> SHOW LIMITS<CR>
No individual triangle interpolation limits will be applied
No whole DTM Z-limits will be applied
TRIGRID> TRIANGLE_LIMITS 3.0 10.0<CR>
TRIGRID> SHOW LIMITS<CR> Individual triangle undershoot limit ................. 3.000 Individual triangle overshoot limit .................. 10.00 Whole DTM lower z-value limit ........................ Unset Whole DTM upper z-value limit ........................ Unset
TRIGRID>

UNITS COMMAND

--------------------------------------------------------------------------------
UNITS

--------------------------------------------------------------------------------
FORMAT: UNITS units

--------------------------------------------------------------------------------
Command parameters:

--------------------------------------------------------------------------------
DESCRIPTION:

The UNITS command enables the user to specify in what units of measurement he wishes to define the DTM window using the WINDOW command, or in what units of measurement details from the header of the DTI file are displayed.

By default metre units are assumed.
The UNITS command should be given before specifying the DTM window the user wishes to specify the window in non-metre units.

If UNITS SECONDS or UNITS LATLONG are used it is assumed that the data read in from the _.DTA and _.NOD files using FILEIN commands are in units of tenth seconds of arc.

UNITS METRES (the default) or UNITS PROJECTION assume that the the data read in using FILEIN commands are in metres or projection units.

Remember that TRIGRID assumes that if UNITS SECONDS or UNITS LATLONG are selected the basic units in the _.DTA snd . NOD files are tenth seconds arc.

The UNITS command does not affect the values specified as arguments to the SIDELENGTH command. These should be expressed in terms of the basic units held in the _.NOD and _.DTA files (i.e. tenth second arc units in the case of geographical SECONDS or LATLONG). In the case of UNITS LATLONG, window values should be expressed as south-west Latitude Longitude north-east Latitude Longitude, not Longitude Latitude. The SHOW WINDOW command will reflect the window extent in both LATLONG units and tenth seconds arc.

--------------------------------------------------------------------------------
Messages:

The following error messages are specific to the UNITS command:

*** ERROR *** Specifying command UNITS
Command qualifiers are METRES,PROJECTION,SECONDS or LATLONG

--------------------------------------------------------------------------------
Examples:

$ TRIGRID<CR>

DTMCREATE module TRIGRID of 14:28:22 20-JAN-89
TRIGRID> FILEIN WEEPY<CR>

_.DTA file LSL$SOURCE_ROOT:[DTMCREATE.TRIGRID]WEEPY_.DTA;8 opened for read _.NOD file LSL$SOURCE_ROOT:[DTMCREATE.TRIGRID]WEEPY_.NOD;8 opened for read _.DER file LSL$SOURCE_ROOT:[DTMCREATE.TRIGRID]WEEPY_.DER;8 opened for read TRIGRID> UNITS LATLONG<CR> TRIGRID> SHOW WINDOW<CR>

Window units are latlong (degrees, minutes and seconds)

Triangulation coverage SW: 4 45 00N 13 44 20E NE: 4 49 00N 13 46 50E (SW: 494600.00 171000.00 NE: 496100.00 173400.00) DTM WINDOW currently undefined.

TRIGRID> WINDOW 4 45 00N 13 45 00 E 4 50 00N 13 46 00E<CR> TRIGRID> SIDELENGTH 10<CR>

X and Y call side lengths assumed equal ( 10.000 10.000 )

Window units are latlong (degrees, minutes and seconds)

Triangulation coverage SW: 4 45 00N 13 44 20E NE: 4 49 00N 13 46 50E (SW: 494600.00 171000.00 NE: 496100.00 173400.00)

Triangulation window SW: 13 45 00N 4 45 00E NE: 13 46 00N 4 50 00E (SW: 171000.00 495000.00 NE: 174000.00 495600.00)

Which with a side length of 10.000 in X and 10.000 in Y gives 61 rows and 301 columns in the dtm

TRIGRID> SHOW WINDOW<CR>

Window units are latlong (degrees, minutes and seconds)

Triangulation coverage SW: 4 45 00N 13 44 20E NE: 4 49 00N 13 46 50E (SW: 494600.00 171000.00 NE: 496100.00 173400.00)

Triangulation window SW: 13 45 00N 4 45 00E NE: 13 46 00N 4 50 00E (SW: 171000.00 495000.00 NE: 174000.00 495600.00) TRIGRID>

WAIT COMMAND

--------------------------------------------------------------------------------
WAIT

--------------------------------------------------------------------------------
FORMAT: WAIT seconds

--------------------------------------------------------------------------------
Command parameters:

--------------------------------------------------------------------------------
DESCRIPTION:

The WAIT command causes processing to be suspended for a specified number of seconds. It is designed for use in software demonstration situations and is of no value in a production flowline.

--------------------------------------------------------------------------------
Messages:

The following warning message is specific to the WAIT command:

*** WARNING *** You must specify the number of seconds to wait

--------------------------------------------------------------------------------
Examples:


TRIGRID> WAIT 4.0<CR>
TRIGRID>

WINDOW COMMAND

--------------------------------------------------------------------------------
WINDOW

--------------------------------------------------------------------------------
FORMAT: WINDOW xmin ymin xmax ymax

--------------------------------------------------------------------------------
Command parameters:

--------------------------------------------------------------------------------
DESCRIPTION:

The WINDOW command is used to define rectangular limits to the area of triangulation to be gridded into a DTI file. The limits must be specified in the order bottom left hand (or south west) corner, then top right hand (or north east) corner.

The WINDOW command can be used to clip data from a triangulation.

There is only one restriction on the WINDOW grid coverage allowed relative to the triangulation extent. The grid DTM must have a minimum of 3 columns and 3 rows. The user may specify that the grid DTM WINDOW extends beyond the triangulation area. Of course there are no original data points for interpolation in the resulting marginal areas and the proclivities of a poorly controlled mathematical surface may not truly represent the real world!

If the user is unsure of the triangulation (X,Y) extent a SHOW WINDOW command will supply this information assuming that the triangulation files have previously been opened with the FILEIN command.

The WINDOW command is obligatory.

--------------------------------------------------------------------------------
Messages:

The following warning messages are specific to the WINDOW command:


*** WARNING **** Unable to read WINDOW arguments

*** WINDOW **** is still unset, please respecify the WINDOW command

*** ERROR **** window values define a zero width window

*** ERROR **** window values define a zero height window

--------------------------------------------------------------------------------
Examples:


TRIGRID> WINDOW 0.0 0.0 120.0 120.0<CR>
TRIGRID>

ZLIMITS COMMAND

--------------------------------------------------------------------------------
ZLIMITS

--------------------------------------------------------------------------------
FORMAT: ZLIMITS real1 real2

--------------------------------------------------------------------------------
COMMAND PARAMETERS:

--------------------------------------------------------------------------------
Description:

By default TRIGRID applies no limits to post height estimation.

The ZLIMITS command specifies lower and upper absolute range limits to enable the user to force a base and ceiling value for the whole model which the interpolation cannot exceed or fall under. This is particularly useful for models containing areas of sea as the lower limit can be set to zero ensuring that the sea cannot receive negative post values under any circumstances. A model whose highest area forms a plateau can be similarly controlled.

--------------------------------------------------------------------------------
Messages:

The following messages are specific to the ZLIMITS command:

*** WARNING *** You must specify lower and upper limit arguments
Lower limit, upper limit?

--------------------------------------------------------------------------------
Examples:


TRIGRID> ZLIMITS 150.0 500.0<CR>
TRIGRID> SHOW LIMITS<CR> Individual triangle undershoot limit ................. Unset Individual triangle overshoot limit .................. Unset Whole DTM lower z-value limit ........................ 150.000 Whole DTM upper z-value limit ........................ 500.000
TRIGRID>

EXAMPLES

--------------------------------------------------------------------------------

EXAMPLES

$ TRIGRID<CR> DTMCREATE module TRIGRID of 14:02:31 3-FEB-89 TRIGRID> @TESTCMD<CR> Command input now being read from SYS$DISK:[]TESTCMD.COM;0 TRIGRID> FILEIN WEEPY _.DTA file LSL$SOURCE_ROOT:[DTMCREATE.TRIGRID]WEEPY_.DTA;9 opened for read _.NOD file LSL$SOURCE_ROOT:[DTMCREATE.TRIGRID]WEEPY_.NOD;9 opened for read _.DER file LSL$SOURCE_ROOT:[DTMCREATE.TRIGRID]WEEPY_.DER;9 opened for read TRIGRID> ZLIMITS 150 500 TRIGRID> TRIANGLE TRIGRID> ENABLE DIAGNOSTICS TRIGRID> WINDOW 494600.00 171000.00 496100.00 173400.00 TRIGRID> SIDELENGTH 10 10 Window units are metres Triangulation coverage SW: 494600.00 171000.00 NE: 496100.00 173400.00 Triangulation window SW: 494600.00 171000.00 NE: 496100.00 173400.00 Which with a side length of 10.00 in X and 10.00 in Y gives 241 rows and 151 columns in the dtm TRIGRID> SHOW ENABLE AUTO_LIMITS ......................................... On DIAGNOSTICS ......................................... On GRAPHICS ............................................ Off SMOOTH .............................................. On (Smooth patch interpolation) NINT ................................................ On ORTHOGONAL .......................................... Off TRACE ............................................... Off TRIGRID> SHOW LIMITS Individual triangle undershoot limit ................. 5.000 Individual triangle overshoot limit .................. 15.000 Whole DTM lower z-value limit ........................ 150.000 Whole DTM upper z-value limit ........................ 500.000 Input files: _.DTA file: LSL$SOURCE_ROOT:[DTMCREATE.TRIGRID]WEEPY_.DTA;9 _.NOD file: LSL$SOURCE_ROOT:[DTMCREATE.TRIGRID]WEEPY_.NOD;9 _.DER file: LSL$SOURCE_ROOT:[DTMCREATE.TRIGRID]WEEPY_.DER;9 Output file: The DTI output file is undefined TRIGRID> SHOW FILES Input files: _.DTA file: LSL$SOURCE_ROOT:[DTMCREATE.TRIGRID]WEEPY_.DTA;9 _.NOD file: LSL$SOURCE_ROOT:[DTMCREATE.TRIGRID]WEEPY_.NOD;9 _.DER file: LSL$SOURCE_ROOT:[DTMCREATE.TRIGRID]WEEPY_.DER;9 Output file: The DTI output file is undefined TRIGRID> SHOW WINDOW Window units are metres Triangulation coverage SW: 494600.00 171000.00 NE: 496100.00 173400.00 Triangulation window SW: 494600.00 171000.00 NE: 496100.00 173400.00 TRIGRID> GO *** WARNING *** The following commands must be given before processing can begin: 1) WINDOW 2) SIZE (or SIDELENGTH) 3) FILEIN 4) FILEOUT *** WARNING *** Indirect file error - returning to terminal input TRIGRID> FILEOUT TESTDTM<CR> TRIGRID> GO<CR> +----------------------------------------------------------------+ | | | Reading in data and point in box markers | | | +----------------------------------------------------------------+ *** WARNING *** No projection information available for DTI header +----------------------------------------------------------------+ | | | Reading slope information | | | +----------------------------------------------------------------+ +----------------------------------------------------------------+ | | | Opening and initialising DTI file | | | +----------------------------------------------------------------+ DTI file LSL$DATA_ROOT:[LSL.DTI]TESTDTM.DTI;0 opened for write File : LSL$DATA_ROOT:[LSL.DTI]TESTDTM.DTI;0 Header : LSLA Data: WORD Units are metres Matrix Coverage SW: 0.00 0.00 NE: 199.50 199.50 Matrix Interval E: 2.10 N: 1.50 Value Range : 0 to 0 +----------------------------------------------------------------+ | | | Generating DTM grid | | | +----------------------------------------------------------------+ ELAPSED: 0 00:00:10.96 CPU: 0:00:00.94 BUFIO: 14 DIRIO: 25 FAULTS: 347

See trigridmsg.html generated from TRIGRIDMSG.RNO.