-------------------------------------------------------------------------------- MODULE IMERGE
-------------------------------------------------------------------------------- REPLACES DAMP utility MER
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IMERGE is an IFF file merge utility. It is used in four circumstances:
By default the CP (Control Point) entry for the output files is taken from the first input file.
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$ IMERGE input-file-spec[,...] output-file-spec
Command qualifiers Defaults
/CP_EXPANSION Take CP entry from first input file.
/[NO]DEBUG /NODEBUG (See text).
/LAYER=integer[,...] Use all layers.
/[NO]LOG /NOLOG
/OUTPUT [=list-file-spec] Do not create a listing file.
/SPLIT [=IFF-file-spec] Create only one output file.
/[NO]UNIQUE_FSN /NOUNIQUE_FSN
Input file command qualifiers Defaults
/LAYER=integer[,...] Use all layers.
Output file command qualifiers Defaults
/CP_EXPANSION Take CP entry from first input file.
/REST_LAYER=integer Create all the input file layers.
/SINGLE_LAYER=integer Create all the input file layers.
Example formats:
$ IMERGE/LOG/SPLIT=restfile/REST_LAYER=integer/OUTPUT=listfile -
Or, alternatively: $ IMERGE/LOG/SPLIT=restfile/REST_LAYER=int/LAYER=(int,...) -Where the layer selections made with /LAYER are applied globally to all the input files._$ infile1,infile2,infile3,infile4 outfile/SINGLE_LAYER=int
Or, alternatively: $ IMERGE_From: /LOG/SPLIT=restfile/REST_LAYER=int - _$ infile1/layer=(int,...), -_$ infile2/LAYER=(int,...), - _$ infile3/LAYER=(int,...), - _$ infile4/LAYER=(int,...), - _$ infile5/LAYER=(int,...), - _$ infile6/LAYER=(int,...), - _$ infile7/LAYER=(int,...) _To: outfile/SINGLE_LAYER
Where IMERGE is put into prompt mode and continuation lines are used. Up to seven input files may be specified.
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_From: input-file-specs _To: output-file-spec--------------------------------------------------------------------------------
input-file-specs
- IMERGE can process up to 7 input files separated by commas. The first input file is parsed against the default file specification 'LSL$IF:IFF.IFF;0'. For any subsequent input file specifications IMERGE parses using the previously supplied file specification as the default for missing specification components. The default thus "rolls along" the command line from left to right, in the same manner as in VMS utilities such as COPY.
output-file-spec
- The output file to contain the selected data. The output file specification is parsed using the last input file as the default for missing specification components.
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/CP_EXPANSION
- by default the CP (Control Point) entry for the output file is taken from the first input file on the command line. The /CP_EXPANSION qualifier allows the user to expand the output file IFF CP entry values to take account of CP entries in all the input files.
Great care must be taken in the use of the /CP_EXPANSION qualifier as it is only appropriate for input files which fit adjacently together to produce a rectangular output map. If IMERGE is unable to produce rectangular control points with the /CP_EXPANSION qualifier a warning is issued and the CP entry of the first input file is used instead.
/DEBUG
/NODEBUG
- reserved for Laser-Scan use. The /DEBUG qualifier invokes special IMERGE code to force output of debug messages.
/LAYER=integer[,...]
- by default IMERGE will copy to the output file all the IFF layers found in each input file. /LAYER enables the user to specify which IFF layers are to be selected for mergeing.
/LAYER is a positionally dependent qualifier. Its effect varies depending upon its placement within the command line:
/LAYER will accept single, multiple or ranges of layer arguments. The maximum number of layers which may be specified is 1024.
/LOG
- this will result in supplementary messages being output. Supplementary messages are generated when a file is successfully opened, and a reassuring message output each time a new IFF layer is created in the output IFF files.
/OUTPUT [=file-spec]
- IMERGE is a complex program, combining IFF files which may have different control points and origin offsets. As many as 7 input files may be combined into a single output file. It is not possible to keep a record of all the input file characteristics in the output IFF file HI (HIstory) entry.
In a production enviroment it is often necessary to keep records of program run details for future reference. The /OUTPUT qualifier enables the user to write to the specified file details of the input and output files, together with a record of the command line specified. The default /OUTPUT file specification is SYS$DISK:IMERGE.LIS;0.
/REST_LAYER=integer
- by default IMERGE will preserve in the rest-output-file all the layer numbers used in the input files. The /REST_LAYER qualifier allows the user to force all the unselected merged data into the rest-output-file layer specified. The /REST_LAYER qualifier is only valid for use with the /SPLIT and /LAYER qualifiers. The layer number specified must lie in the range 0 to 32767.
/SINGLE_LAYER=integer
- by default IMERGE will preserve in the selections output file all the layer numbers used in the input files. The /SINGLE_LAYER qualifier allows the user to force all the merged data sent to the selections output file into the layer specified. The layer number specified must lie in the range 0 to 32767.
/SPLIT [=rest-IFF-file]
- split input IFF files into two separate output files on the basis of IFF layer. This qualifier can only be used in conjunction with the /LAYER qualifier. The two IFF output files which result from specifying the /SPLIT qualifier are referred to as the "selections-output-file" and the "rest-output-file". The selections-output-file contains all the features which were within IFF layers selected from the input IFF files and the rest-output-file contains the rest of the layers i.e. those which were not selected.
The optional argument to /SPLIT is the file-spec of the rest-output-file. If no argument is given, then the default LSL$IF:IMERGE_SPLIT.IFF;0 is used. The rest output IFF file may use the layer numbers used in the input files or a new single layer may be specified by using the /REST_LAYER qualifier.
/UNIQUE_FSN
/NOUNIQUE_FSN
- preserves the FSN's of the first file in the list of input files, and, by using the maximum FSN of the first file, automatically renumbers the FSN's in subsequent input files to create unique FSN's in the output file. If this qualifier is selected, the FSN's in the first input file are assumed to be unique and in an acsending order. The default is /NOUNIQUE_FSN which retains the FSN's of each of the input files, thus allowing the possibility of duplicate FSN's in the output file.
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Although IMERGE is the IMP IFF file merge utility it offers a range of file processing functions within a production environment. It is used in four circumstances:
In its most obvious role IMERGE is used to concatenate two or more IFF files into a single map, possibly offsetting the string coordinates as required using information from the input file IFF MD (Map Descriptor) entries. Up to 7 input files may be specified for a single run of IMERGE.
The input files are merged together on the basis of IFF layer. Each input file is opened in turn and its contents scanned for IFF NO (start of layer) entries. The address of each NO within each input file is tabulated in a layer table. After scanning, the current input file is closed and the next input file opened. When all the input files have been opened, scanned and closed again IMERGE begins the process of file concatenation.
The table of scanned layers is sorted on the basis of layer number and the lowest layer number found in the input files is output first; each input file containing a fragment of the current layer number is opened and its layer fragment copied to the output file.
If examination of the layer table shows that further fragments of the current layer number lie in the currently open input file, then these too are found and copied to the output file.
The current input file is closed and the next input file containing layer fragments which match the current layer number is opened and the process repeated.
When all layer fragments of the current layer number have been extracted from all the input files and copied to the output file, the layer table is read again for the next highest layer number. The process of input file opening and layer fragment extraction is repeated until all layer fragments in the input files have been concatenated into complete layers in the output file.
The output file now has only one map containing all the layers found in all the input files. The layers are ordered on the basis of ascending layer number, all input layer fragments of the same layer number are concatenated into a single layer. The output file IFF header entries are set according to the following rules:
Because of its ability to concatenate layer fragments, both between and within IFF files, IMERGE has a special place in the LAMPS production environment.
Due to the nature of the digitising process, either using LASERAID or a manual table system, IFF files will usually contain data from several digitising sessions. Each time a digitising session is started the IFF file is extended with a new header sequence of NS (New Section), CC (Cubic Coefficients) and CP (Control Points) entries. A new layer is then opened and the additional digitising added.
It is essential that the multiple sections of an IFF file and the fragmentary layers be concatenated before further LAMPS processing may be conducted. LAPROCESS must first be used if the IFF file was digitised using LASERAID. Then either IMERGE or LITES2 may be used to consolidate all the layer parts from different sessions, before further IMP processing. If IMERGE is used the IFF file should be merged to itself, for example:
$ IMERGE/LOG SHEET274NE_CONTOURS.IFF SHEET274NE_CONTOURS.IFF
The consolidated file will be given the next highest version number to that of the input file.
IMERGE can be used to merge out of the input files only selected layers. The layers are selected using the /LAYER qualifier. The effect of the /LAYER qualifier is dependent upon its position within the command line. See the QUALIFIERS section for a detailed description of /LAYER.
IMERGE can be used to split input IFF files into two separate output files on the basis of IFF layer.
The output IFF files may use the layer numbers used in the input files or a new single layer may be specified for each output file.
The two IFF output files which result from specifying the /SPLIT qualifier are referred to as the "selections output file" and the "rest-output-file".
The selections-output-file contains all the features which lay within IFF layers selected from the input IFF files and the rest-output-file contains the rest of the layers, i.e. those which were not selected. It is only possible to split an input IFF files into two output files if layer selections have been specified with /LAYER (q.v.).
With the release of the IMP package several enhancements to the IFF library were announced. One of the most powerful of these is the type 2 MD (Map Descriptor) entry.
One of the features of the type 2 MD is the ability to hold an origin offset. This origin offset is a coordinate pair which when added to string coordinate values, will give the coordinates their true position.
One advantage of having an origin offset is the ability to hold and manipulate large coordinate values within the IFF file without loss of precision. The origin offset should be chosen to be largest number which can be subtracted from all the coordinates in the file without making any of them negative. Typically, the origin offset will be the coordinate values of the south west corner of a map sheet.
The IFF library has supported customer specific origin offsetting facilities for a long time within special MH (Map Header) entries. IMERGE does not recognise the offsets in such headers. The type 2 MD origin offset allows IMERGE to provide all the offsetting functionality of previous customer specific utilities as relative offsets between map sheets may be performed now using IMERGE.
IFF files having type 1 MD entries without origin offsets may be easily converted to type 2 MD standard by using ITRANS/DESCRIPTOR. It is of course essential that the origin offset be set up correctly.
IMERGE applies the origin offset in the following manner.
If input files with a mixture of MD types are supplied to IMERGE the output file will be worthless if those with type 2 MDs have set origin offset fields while those with type 1 MDs have not taken account of the origin offset. The warning message:
NOV2MD, IFF map descriptor in 'file-spec' is not version 2
should always be heeded and the user should ensure that the coordinates in the specified file are in the correct coordinate space.
IMERGE preserves compatibility with IFF files having type 1 Map Descriptors in the following manner:
In addition to providing an origin offset facility, IMERGE also conducts checks on the map projection data held in a type 2 MD.
The map projection data held in the MD of the first input file is considered to be "truth". The second and subsequent input file MD entries are checked for consistency of map projection constants. Spheroid, measurement unit, projection and projection parameters are compared with those of the first input file. A warning message is issued if any conflict is found. For instance it is clearly useless to merge together files having coordinates on different projections.
Because IMERGE can accept up to 7 input files it is impossible to copy the IFF HI (HIstory) entries from all the input files to the output files.
If any one of the input files contains a HI entry, a new HI is created in the output files. The selections-output-file has the words "Merge_: select" written into the function field of the HI. The optional rest-output-file has the words "Merge_: rest" written into the function field of the HI.
If no input file has a HI entry then no HI entry is created in the output file.
To enable the user to keep track of the history of the input files after merging, IMERGE offers the user the /OUTPUT qualifier. The file created by /OUTPUT contains a listing of the HI entries of all the input files (together with listings of their CP (Control Point) entries and user process information). This file may be stored (or printed) as a record of the merge operation and the status of the input files before they became unified into a single new output file.
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$ IMERGE CONT_NE,CONT_NW,CONT_SE,CONT_SW CONTOURSELAPSED: 00:00:54.98 CPU: 0:00:42.02 BUFIO: 85 DIRIO: 595 FAULTS: 284 $
$ $ IMERGE DUA0:[IFF.USER.EXPERIMENTS]F204.IFF F204.IFF
$ $ IMERGE/LAYER=(10,14) SW.MER/LAYER=(7,9), -
This complex example shows IMERGE being used to select only specified
layers from the input files
LSL$IF:SW.MER;0,
DUA0:[IFF.USER.EXPERIMENTS]SE.IFF;0,
DUA0:[IFF.USER.EXPERIMENTS]NE.IFF;0 and
DUA0:[IFF.TEST]NW.IFF;0. The missing file-speccomponents of the first
input file specification have been derived by parsing against the Laser-Scan
default IFF file specification LSL$IF:IFF.IFF;0. However, the user has given
the second input file a full file specification, including device and
directory. IMERGE always parses command line file specifications using the
previously supplied file specification as the default for missing specification
components. The default thus "rolls along" the command line from left to right,
in the same manner as in VMS utilities such as COPY. The output file in this
example has thus become DUA0:[IFF.TEST]WHOLEMAP.IFF;0.
The /LAYER qualifiers have the following effect.
The net result of the global and the two local /LAYER qualifiers is that the output file will contain only IFF layers 1, 7, 9, 10 and 14 from some of the various input files.
$ $ IMERGE SW,SE/OUTPUT=MAP7 DUA0:[PROJECT.QUARRIES]SOUTH
This example illustrates the use of the /OUTPUT qualifier to specify a file to contain listed details of the IFF HI (HIstory) and CP (Control Point) entries, together with origin offset information for the input files. Details of the user process and command line qualifiers used are also recorded. The /OUTPUT listing file is parsed against the default specification SYS$DISK:IMERGE.LIS, resulting in the file specification SYS$DISK:MAP7.LIS.
IMERGE has detected two errors in the input files and has issued warning messages. The first input file, DUA0:[LSL.IFF]SW.IFF;1, has a type 1 IFF MD (Map Descriptor) entry. No origin offset information is available for this file. The second file, DUA0:[LSL.IFF]SE.IFF;1, has a type 2 MD entry but the entry has not been set by using either ITRANS/DESCRIPTOR or ISTART. Again, no origin offset information is available for this file. $STATUS is set to SS$_NORMAL.
$ $ IMERGE/LOG/SPLIT=UNUSED.IFF/REST_LAYER=12
This example shows the use of the /SPLIT and the /REST_LAYER qualifiers. Because /SPLIT has been specified, those IFF layers which have been selected using the /LAYER qualifier will be written to the selections-output-file DUA0:[LSL.IFF]QUARRY_PLAN_3.IFF;12. Those layers not selected from the input files, i.e. the rest of the input layers, will be written to the /SPLIT rest output file DUA0:[LSL.IFF]UNUSED.IFF;0. The /REST_LAYER qualifer has been used to specify that all the layers written to the rest-output-file shall be consolidated into a single output layer, layer 12.
The /LOG qualifier has been specified. It causes messages to be output when files are opened and shows the data being split between the two IFF output files. Notice that layer 2 has not been written to the selections-output-file (DUA0:[LSL.IFF]QUARRY_PLAN_3.IFF;12) despite the /LAYER=(1,2,8) qualifier arguments applied to DUA0:[LSL.IFF]BALLAST.IFF;6. This means that DUA0:[LSL.IFF]BALLAST.IFF;6 contains no layer 2.
$ $ IMERGE/UNIQUE_FSN
This example illustrates the use of the /UNIQUE_FSN qualifier to force the FSN's of the output file to be unique. Users must note that the FSN's in the first input file should be unique and in an ascending order. However, the program does check that FSN's are in ascending order, and if not a warning warning message is output, as shown in this example.
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These messages give information only, and require no immediate action by the user (except perhaps to verify that the correct options have been selected). Most will only appear if /LOG has been specified on the command line, unless they are used to provide supplementary information after an error has occurred.
CONFLPROJ, conflicting map projection in 'file-spec'
Explanation: If mergeing from more than one input file IMERGE takes pains to check that the type 2 IFF Map Descriptors are all set to common values for projection, measurement units, spheroid etc. The first input file is considered to have the definitive Map Descriptor information. This message indicates that the input files contain data on different projections.
User action: Use ITRANS to transform all the input files into a common projection, measurement system etc.
CONFLSPHERE, conflicting spheroid in 'file-spec'
Explanation: If mergeing from more than one input file IMERGE takes pains to check that the type 2 IFF Map Descriptors are all set to common values for projection, measurement units, spheroid etc. The first input file is considered to have the definitive Map Descriptor information. This message indicates that the input files contain data on different spheroids.
User action: Use ITRANS to transform all the input files into a common projection, measurement system etc.
CONFLUNIT, conflicting map units in 'file-spec'
Explanation: If mergeing from more than one input file IMERGE takes pains to check that the type 2 IFF Map Descriptors are all set to common values for projection, measurement units, spheroid etc. The first input file is considered to have the definitive Map Descriptor information. This message indicates that the input files contain data in different measurement systems.
User action: Use ITRANS to transform all the input files into a common projection, measurement system etc.
CONFLMDPAR, conflicting projection parameters in 'file-spec'
Explanation: If mergeing from more than one input file IMERGE takes pains to check that the type 2 IFF Map Descriptors are all set to common values for projection, measurement units, spheroid etc. The first input file is considered to have the definitive Map Descriptor information. This message indicates that the input files contain data relating to different projection parameters.
User action: Use ITRANS to transform all the input files into a common projection, measurement system etc.
DEF, default values for IFF header entries will be used in output file 'file-spec'
Explanation: Not all IFF file header entries were present in the input IFF files. This is most irregular, and is probably the result of output from a badly written user routine or the mis-use of IPATCH in /WRITE mode. IMERGE will supply default values for any of the following entries which were missing:
User action: Determine the cause of the input file corruption and rectify. Check the IMERGE output files to ensure that the default IFF header entry values are acceptable.
FIRSTCP, defaulting to CP entry of first input file
Explanation: The /CP_EXPANSION qualifier has been specified for use on input files which will not form a rectangular merged map area. IMERGE will use the Control Point entry of the first input file as the pattern for the output files CP entry.
User action: Consider why the /CP_EXPANSION qualifier was specified. Modify the CP entry in the IFF output files using IPATCH/WRITE.
NOIFFHI, file has no IFF HI entry
Explanation: The input IFF file that is currently open is of the old pre-IMP pattern and probably also lacks a type 2 map descriptor (for which a separate warning will be issued).
User action: None.
USE, using IFF 'code' entry from 'file-spec'
Explanation: The first input file lacked the specified IFF header entry. IMERGE attempts to continue execution by taking the missing entry from an input file which was specified later in the command line. The lack of an IFF header entry is most irregular, and is probably the result of output from a badly written user routine or the mis-use of IPATCH in /WRITE mode.
User action: Determine the cause of the input file corruption and rectify. Check the IMERGE output files to ensure that the substitute IFF header entry values are acceptable.
WRSELLAY, writing selected layers to 'file-spec'
Explanation: This is output as an indication of what IMERGE is currently doing. IMERGE has scanned all the input files for layer fragments and has built up internal tables to indicate the addresses of input layer fragments, the order of layer output and the order of input file opening. IMERGE has now started output of the concatenated layer fragments to the selections-output-file.
User action: None.
WRESTLAY, writing remaining layers to 'file-spec'
Explanation: This is output as an indication of what IMERGE is currently doing. IMERGE has scanned all the input files for layer fragments and has built up internal tables to indicate the addresses of input layer fragments, the order of layer output and the order of input file opening. IMERGE has now started output of the concatenated layer fragments to the rest-output-file.
User action: None.
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These messages indicate that IMERGE has been unable to guarantee that a specified feature has been correctly processed.
CONFLMD, conflicting Map Descriptor information
Explanation: If mergeing from more than one input file IMERGE checks that the type 2 Map Descriptors are all set to common values for projection, measurement units, spheroid etc. The first input file is considered to have the definitive Map Descriptor information. The accompanying messages will indicate what aspect of the Map Descriptor is at fault and in which file.
User action: Use ITRANS to transform all the input files into a common projection, measurement system, etc. Re-run IMERGE.
DUPINFIL, input IFF files share the same specification
Explanation: IMERGE checks that the user has not specified the same input file more than once. "Double digitising" in the output file will result if IMERGE is allowed to proceed.
User action: Respecify the command line but omit one of the duplicate file-specs.
DUPOUTFIL, output IFF files share the same specification
Explanation: If the user uses the /SPLIT=filespec qualifier, IMERGE checks that the user has not supplied the same specification for the rest output file and the selections-output-file. It would be very dangerous to continue as although the two files output will contain different data, they will have adjacent version numbers in the same directory and are liable to be purged. In addition the files will have almost identical creation times and will be difficult to distinguish within a production environment.
User action: Respecify the command line, ensuring that the output files do not share the same specification.
INAPPCPS, inappropriate CP entries for /CP_EXPANSION qualifier
Explanation: The /CP_EXPANSION qualifier has been specified for use on input files which will not form a rectangular merged map area.
User action: Consider why the /CP_EXPANSION qualifier was specified. As IMERGE is unable to expand the control points for you, respecify the IMERGE command line but omit the /CONTROL_POINTS qualifier. After re-runing IMERGE use IPATCH to change the control point entry in the output files.
INVALCP, inappropriate CP entry for /CP_EXPANSION qualifier in file 'file-spec'
Explanation: Either the input file lacks a CP entry or a CP entry has been read that has zero extent.
User action: Check the offending file with IINFO and modify the CP entry using IPATCH/WRITE
INVCPQUAL, /CP_EXPANSION specified when mergeing input file to itself
Explanation: This would be a pointless exercise as the Control Points will be EXACTLY the same regardless of the /CP_EXPANSION qualifier.
User action: Re-specify the command line.
INSUFHD, insufficient IFF header entries in input files
Explanation: The input IFF files do not have all the usual (and required) header entries. This is most irregular, and is probably the result of output from an erroneous program, or the mis-use of IPATCH in /WRITE mode. IMERGE will apply default values any of the following entries which were missing:
User action: Determine the cause of the input file corruption and rectify. Check the IMERGE output files to ensure that the default IFF header entry values are acceptable.
MISSCC, missing IFF CC entry in first input file
Explanation: The first IFF file does not have a CC (Cubic Coefficients) entry. This is most irregular, and is probably the result of output from a badly written user routine or the mis-use of IPATCH in /WRITE mode. IMERGE will attempt to take the CC entry from the second or subsequent input file, and use this as the CC entry for the output files.
User action: Determine the cause of the input file corruption and rectify. Check the IMERGE output files.
MISSCC, missing IFF CP entry in first input file
Explanation: The first IFF file does not have a CP (Control Points) entry. This is most irregular, and is probably the result of output from a badly written user routine or the mis-use of IPATCH in /WRITE mode. IMERGE will attempt to take the CP entry from the second or subsequent input file, and use this as the CP entry for the output files.
User action: Determine the cause of the input file corruption and rectify. Check the CP entry in the IMERGE output files. If /CP_EXPANSION was specified then the results of the control point expansion will probably be erroneous.
MISSMH, missing IFF MH entry in first input file
Explanation: The first IFF file does not have a Map Header entry. This is most irregular, and is probably the result of output from a badly written user routine or the mis-use of IPATCH in /WRITE mode. IMERGE will attempt to take the MH entry from the second or subsequent input file, and use this as the MH entry for the output files.
User action: Determine the cause of the input file corruption and rectify. Check the IMERGE output files.
MISSNS, missing IFF NS entry in first input file
Explanation: The first IFF file does not have a New Section entry. This is most irregular, and is probably the result of output from a badly written user routine or the mis-use of IPATCH in /WRITE mode. IMERGE will attempt to take the NS entry from the second or subsequent input file, and use this as the NS entry for the output files.
User action: Determine the cause of the input file corruption and rectify. Check the IMERGE output files.
NOMD, no map descriptor found in 'file-spec'
Explanation: The specified IFF file does not have a map descriptor entry. This is most irregular, and is probably the result of output from a badly written user routine or the mis-use of IPATCH in /WRITE mode. IMERGE will attempt to continue.
User action: Determine the cause of the input file corruption and rectify. Check the IMERGE output files.
NOV2MD, IFF map descriptor in 'file-spec' is not version 2
Explanation: IMERGE expects input files to have type 2 map descriptors as it offers offset merging functionality based on the contents of the map descriptor. IMERGE is downwards compatible with old pattern IFF files which have type 1 map descriptors, but no origin offset facility is supported for the earlier pattern files.
User action: If origin offsetting is required use ITRANS/DESCRIPTOR to create a copy of the IFF file having a type 2 map descriptor.
QUALPOSINV, /LAYER qualifier positioning invalid
Explanation: The /LAYER qualifier must appear AFTER the command verb but BEFORE the input file parameters if global layer selections are desired. Alternatively the /LAYER qualifier may be placed AFTER any of the input file parameters but BEFORE the output file parameter if individual input file layer selections are desired.
User action: Respecify the command line.
UNSETMD, map descriptor in 'file-spec' is unset
Explanation: The Map Descriptor in the specified input file is unset.
User action: If origin offsetting is required or other input files have characteristics which require the map descriptor to be set, use ITRANS/DESCRIPTOR to set up the map descriptor. Re-run IMERGE.
UNEXPENT, unexpected IFF 'code' entry at address 'int' in IFF file 'file-spec' - attempting to continue
Explanation: The specified IFF entry type was found among the header entries of the specified IFF file. This is most irregular, and is probably the result of output from an erroneous program, or the mis-use of IPATCH in /WRITE mode. IMERGE will attempt to continue.
User action: Determine the cause of the input file corruption and rectify. Check the IMERGE output files.
UNSORTFSN, FSN's in first IFF file are not in ascending order at
Layer 'number', FSN 'code'
Explanation: The current FSN found is either duplicated or not in order. IMERGE will attempt to continue leaving those duplications or irregularly-ordered features in the output file(s).
User action: Check the first input file to ensure that all FSN's are unique and in an ascending order.
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These messages indicate an error in processing which has caused the program to terminate. The most likely causes are a corrupt or otherwise invalid input IFF file, or an error related to command line processing and file manipulation. The output files will be deleted.
EONOTFND, IFF EO entry not found in 'file-spec'
Explanation: While scanning the specified IFF input file for layer fragments an IFF EO entry was found to be missing or the address of an EO was incorrect within the corresponding NO entry.
User action: Use LITES2 (or ITOTEXT followed by IFROMTEXT) to repair the file.
ILEGLAY, illegal IFF layer number 'integer'
Explanation: The layer number specified as an argument to a /LAYER qualifier does not lie in the range 0 to 32767 or contains a non-numeric character.
User action: Respecify the command line.
IFFNOLYRS, no layers found in IFF file 'file-spec'
Explanation: IMERGE operates at the IFF layer level. Unfortunately, the specified input file does not contain any layers at all.
User action: Use ITOTEXT followed by IFROMTEXT to repair the file. Re-run IMERGE.
MERNOLYRS, no selected layers to merge in IFF file 'file-spec'
Explanation: Layer selection was specified with the /LAYER qualifier. The specified input file contains none of the selected layers.
User action: Use IINFO to determine the layers within the offending file. Re-specify the IMERGE command line.
MERNOSPLYRS, no layers left for /SPLIT. All have been selected
Explanation: Although the user expected layers to be left over after selections with /LAYER there are none left to put into the rest-output-file. The /SPLIT qualifier was therefore superfluous and an empty rest-output-file would result if execution was allowed to continue.
User action: Re-specify the command line, either reducing the number of layers selected for the selections-output-file or omitting completely the /SPLIT qualifier.
MISSQ, missing qualifier; /REST_LAYER requires /LAYER
Explanation: If /SPLIT is specified without having made layer selections from the input files there can be no layers left after selection for the rest-output-file. Without /SPLIT and /LAYER, /REST_LAYER is useless.
User action: Consider why you want the /SPLIT qualifier and then re-type the command line making appropriate layer selections.
MISSQ, missing qualifier; /SPLIT requires /LAYER
Explanation: If /SPLIT is specified without having made layer selections from the input files there can be no layers left after selection for the rest output file.
User action: Consider why you want the /SPLIT qualifier and then re-type the command line making appropriate layer selections.
TOMNYLAY, too many layers found in input files (max allowed is 'integer')
Explanation: The input files together contain more than the indicated maximum number of layers that IMERGE can tabulate.
User action: Consider why there are so many layers. Run IMERGE on only some of the input files at a time if you wish to concatenate a lot of layer fragments, then merge together the files with the concatenated layers.
UNEXPEOF, unexpected end of IFF file 'file-spec'
Explanation: The specified input IFF file terminated before an IFF EJ entry was encountered.
User action: Use IMEND to correctly terminate the file. Re-run IMERGE on the repaired IFF file. If the problem persists try reading the file into LITES2 and then exit. Re-run IMERGE.
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These messages indicate a fatal error in processing which has resulted in immediate program termination and may indicate an error in the program itself. The output files will be deleted.
NONOTFND, IFF NO entry not found in 'file-spec'
Explanation: IMERGE has scanned all the input files for layer fragments and has built up internal tables to indicate the addresses of input layer fragments, the order of layer output and the order of input file opening. IMERGE has started output of the concatenated layer fragments to the rest output file but now cannot find one of the fragments in the specified file. The address of the offending layer is probable corrupt.
User action: Please take a copy of all the input files and then notify Laser-Scan. Try ITOTEXT followed by IFROMTEXT to repair the file. Re-run IMERGE.
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In addition to the above messages which are generated by IMERGE itself, other messages may be produced by the command line interpreter (CLI) and by Laser-Scan libraries. In particular, messages may be generated by the IFF library. These are introduced by '%IFF' and are documented in the IFF library users' guide. In most cases IFF errors will be due to a corrupt input file, and this should be the first area of investigation. If the cause of the error cannot be traced by the user and Laser-Scan are consulted, then the input file should be preserved to facilitate diagnosis.