Laser-Scan Ltd.

Software Product Specification

MATRIX package

Issue 4.6 17-Sep-1993
Copyright (C) $$year Laser-Scan Ltd
Science Park, Milton Road, Cambridge, England CB4 4FY  tel: (0223) 420414
Document "MATRIX SPS"                                   Category "SALES - Spec"
Document Issue 1.0   Dave Catlow                        14-Jan-1987
         Issue 2.0   Dave Catlow,Tim Hartnall           20-Jan-1988
         Issue 3.0   Dave Catlow                        05-May-1988
         Issue 4.0   Dave Catlow                        02-Sep-1988
         Issue 4.1   Dave Catlow                        15-Feb-1989
         Issue 4.2   Clarke Brunt                       25-Apr-1991
         Issue 4.3   Jon Barber                         25-May-1991
         Issue 4.4   Jon Barber                         05-May-1992
         Issue 4.5   Jon Barber                         30-Jul-1993
         Issue 4.6   Jon Barber                         17-Sep-1993



The Laser-Scan MATRIX package is the support package for all Laser-Scan DTM generation and manipulation software, and other Laser-Scan software using the DTI matrix file format.

There are 4 Laser-Scan DTM production and manipulation packages:

Package MATRIX contains:


The DTM utility programs within the MATRIX package require grid based data to be held in Laser-Scan's DTI (*Digital *Terrain *Image) format. Data output and data conversion is to other DTI format grid files, to Laser-Scan vector IFF (*Internal *Feature *Format) files, or to text files.


The following computer hardware requirements are needed to run MATRIX.


MATRIX modules run under VAX VMS Version 5.4-3 (or later version, assuming continued upwards compatibility by DEC). MATRIX co-exists with other interactive and batch processes.

For the use of Motif on a VAXstation, the "DECwindows Motif" layered product from DEC is required. The "VMS DECwindows Developers Kit for Motif" is not adequate.

For the use of UIS on a VAXstation, VAX VMS Workstation Software (VWS) version 4.3 or later is required.

A minimum working set of 4000 pages is recommended. Larger working sets will help performance, particularly with large matrix files.

Laser-Scan's *IFF *Map *Processing package (IMP) is a prerequisite. Laser-Scan's LITES2 interactive digitising and editing software is recommended for digitising and editing vector input data. LASERTRAK automated digitising is recommended for large numbers of input documents.


The minimum hardware and software requirements for any future version of this product may be different from the minimum hardware requirements for the current version.


MATRIX is a fully supported Laser-Scan standard software product.


The MATRIX package contains DTILIB which provides a library of functions which enable an applications program to access DTI files, and perform basic I/O operations on both the header and data areas. The following groups of routines are provided within the library:

The library allows up to 9 DTI files to be opened simultaneously.

It should be noted that the DTILIB functions utilise the memory mapping routines (eg. VIO$OPEN_SEC) within the Laser-Scan library LSLLIB, along with other LSLLIB I/O functions. An applications program that utilises DTILIB must therefore be linked with LSLLIB. A shared image of LSLLIB routines is provided as part of the Laser-Scan kernel LSLSYSTEM package.


The MATRIX package consists of DTILIB and the following component modules:


The module DTIVIEW allows elevation data held in a grid DTM to be viewed as a 3-dimensional image. The module has facilities to generate a 3-D terrain image using either a parallel (isometric) or perspective projection. The terrain image may be output to a range of vector graphic devices, or to an IFF vector file.

The main features of DTIVIEW are:

The facility to overlay data describing surface features (eg. rivers and woodland) upon a 3-D terrain image is available with the TVES module DTIVIEWEXTRA.


The module DTIEDIT enables the interactive display and editing of a Laser-Scan Digital Terrain Image (DTI) file, using a VT100 compatible display. In addition a number of non-interactive editing commands are provided, and an option to output the matrix display to a line printer or file.

The program will handle all types of digital terrain image headers, and currently supported data formats (ie. byte, word, longword, real and bit).

The matrix is displayed as an image of up to 26 classes, with each class (ie. band of values) being represented by an alphabetic character (lowest A, highest Z). The class interval, range of values displayed, and the area of the matrix displayed and available for editing may be set by the user.

Interaction with the display is via the keypad keys.

The main features of DTIEDIT are:


DTIBLEND is the MATRIX *Digital *Terrain *Image (DTI) file edge blend utility. It takes as input two DTI files, usually containing terrain elevation models, and edge matches them to avoid value discontinuities at the matrix adjoining edge. Options are provided to hold one matrix unchanged while smoothing the other to match it, or to smooth both matrices to a common mean along the edge. An option is provided to read in IFF vector data for use as control to the smoothing process.

The data in all the input DTI files should be at the same grid resolution (no grid interpolation is performed).

Changes of DTI file grid resolution should be performed first using the DTITRANS utility.

DTIBLEND offers the following features:


DTITILE will either merge up to 8 DTI (*Digital *Terrain *Image) files into a larger DTI output file, or will extract an area of interest from an input DTI file and write this to a separate DTI output file. In addition DTITILE may be used to create void areas in a DTI file.

The data in all the input DTI files should be at the same grid resolution (no grid interpolation is performed).

The output DTI file will be produced at the same grid resolution as the first input DTI file

Changes of DTI file grid resolution should be performed first using the DTITRANS utility.

DTITILE offers the following features:


The module DTICOMBINE allows data values in one or more (up to 8) DTI files to be combined according to user specified arithmetic operations. The module creates an output DTI file containing the resulting data values.

Optionally only data values that lie within a user specified rectangular window may be processed.

DTICOMBINE is used to perform overlay operations and determine differences between DTI files.

DTICOMBINE may use the following operators and functions in the expression:

Operators are chosen from the set:

  Arithmetic operators:
	unary minus		-		e.g.	- A
	addition		+		e.g.	A + B
	subtraction		-		e.g.	A - 3
	division		/		e.g.	A / 2
	multiplication		*		e.g.	A * 3
	exponentiation		**		e.g.	A **1.2

   Bitwise operators:
	bitwise AND		&		e.g.	A & 127
	bitwise OR		|		e.g.	A | B
	bitwise NOT		~		e.g.	~ A
	bitwise XOR		^		e.g.	A ^ B

   Logical operators:
	logical AND		&&		e.g.	( A > 1 ) && B
	logical OR		||		e.g.	(A<3) || (B>20)
	logical NOT		~~		e.g.	~~(A = 4)
	logical XOR		^^		e.g.	(A = 3)^^(B < 3)

   Relational operators:
	less than		<		e.g.	A < 3
	greater than		>		e.g.	D > 4
	equal to		=		e.g.	A = B
	not equal to		<>		e.g.	A <> 6.7
	less than or equal to	<=		e.g.	C <= A
	greater or equal to	>=		e.g.	B >= (10*A)

Functions available are:

	absolute		ABS		e.g.	ABS(A)
	nearest integer		NINT		e.g.	NINT(3.1415927)
	arc cosine		ACOS		e.g.	ACOS(.32)
	arc sine		ASIN		e.g.	ASIN(A)
	arc tangent		ATAN		e.g.	ATAN(B/A)
	cosine			COS		e.g.	COS(90)
	sine			SIN		e.g.	SIN(D)
	tangent			TAN		e.g.	TAN(A/B)
	maximum			MAX		e.g.	MAX(A,B,C,D,E,F)
	minimum			MIN		e.g.	MIN(2,D,B)
	conditional		IF		e.g.	IF(A>3,A,B)


DTIROTATE is a matrix manipulation module to permit reordering of DTI format DTM rows and columns to suit customer requirements.

DTIROTATE offers the following features:


The module DTI2TEXT converts a DTI file into a formatted text file. The record format of the text file may be user defined at run-time. Integer and floating point format output may be specified.

DTI2TEXT provides a data window facility to enable the user to select sub-areas of the DTI file for text conversion.


The module DTICONVERT enables a user to convert between the header and data type formats supported within Laser-Scan's Digital Terrain Image (DTI) raster files. This conversion may be carried out to reduce the size of raster images stored on disk, or to prepare data for display using TVES modules such as ROVER.

The module allows conversion:


The module DTIPATCH enables the contents of a DTI header to be modified. Currently DTIPATCH operates only on the record fields that are common to all DTI header types (ie. matrix extent values, grid interval values, minimum and maximum range values and data corner and orientation).

DTIPATCH is an interactive prompt driven program.


The module DTITRANS performs the following sets of operations on grid data held in a DTI format:

The module is applicable to all types of raster data, but is primarily used to transform satellite or digital terrain data.


The module DTIFROMTEXT converts a text file into a DTI file. The program supports a range of text file input formats, controlled by the qualifiers, including the reading of z height data only, or x,y,z data, and a limited range of customised translations.