Laser-Scan Ltd.

Software Product Specification

Copyright (C) $$year Laser-Scan Ltd
Science Park, Milton Road, Cambridge, England CB4 4FY  tel: (0223) 420414
Document "DTMCREATE SPS"                                Category "SALES - Spec"
Document Issue 1.0   Tim Hartnall                 14-Jan-1987
Document Issue 1.1   Tim Hartnall                 25-Jun-1987
Document Issue 2.0   Tim Hartnall                 20-Jan-1988
Document Issue 2.1   Tim Hartnall                 04-May-1988
Document Issue 2.2   Steve Townrow                 13-Apr-1992
Document Issue 2.3   Steve Townrow                 30-Apr-1992
Document Issue 2.4   Clarke Brunt                  1-Sep-1999



DTMCREATE is a semi-interactive Digital Terrain Model (DTM) production system.

The DTMCREATE package is one of 3 Laser-Scan DTM production and manipulation packages:

All three packages are supplied with a background package "MATRIX". Package MATRIX contains Laser-Scan DTI (*Digital *Terrain *Image) format DTM management programs, a basic DTM viewing program and a DTI manipulation subroutine library for applications programmers. (See separate SPS for MATRIX package)


Data input to the DTMCREATE package is from Laser-Scan IFF (*Internal *Feature *Format) files on magnetic disk. Data may consist of contour strings and/or spot heights, clifflines and three dimensional river and ridgeline strings. Whole IFF layers or individual feature codes may be nominated as indicating slope breaklines, clifflines, ridgelines and rivers at run time.


The DTMCREATE package provides DTM output to a Laser-Scan internal type DTI (Digital Terrain Image) file. Format converters are available to produce alternative DTM formats. Examples of such format conversions are UHL1 or TED4 type Defense Mapping Agency file format, or simple ASCII text listings.


DTMCREATE offers the following features:



The following computer hardware requirements are needed to run DTMCREATE.


DTMCREATE modules run under OpenVMS VAX Version 5.5-2 (or higher version, assuming continued upwards compatability by DEC), or OpenVMS Alpha Version 6.2 (or higher), concurrently 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.

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 and software requirements for the current version.


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


DTMCREATE consists of the following component modules:

MODULE TRIANG (triangulation)

TRIANG is the spatial structure generation program that defines source data inter-node relationships based on a Delaunay triangulation. It produces two binary files which serve as input to other DTMCREATE package programs.

TRIANG features are:

MODULE TRIDER (slope derivative estimation)

TRIDER takes as input the binary files which define the triangulation structure created by TRIANG (or output by TRIEDIT) and estimates the first derivatives of slopes at each node within the triangulation. Output is to a binary file which is used as input to TRIGRID.

TRIDER offers the following features:

MODULE TRIGRID (DTM grid generation)

TRIGRID is a grid (DTM) generation program operating on the data structure created by TRIANG or TRIEDIT and TRIDER,

TRIGRID offers the following features:

MODULE TRIEDIT (triangulation graphical editor)

TRIEDIT is a triangulation graphical editor, including structure display and contouring, to adjust the automatically derived inter-node relationships to suit special purposes, and to allow insertion of additional special purpose strings.