Laser-Scan Ltd.

Software Product Specification

POLYGONS package

For LAMPS V4.3
Copyright (C) $$year Laser-Scan Ltd
Science Park, Milton Road, Cambridge, England CB4 4FY  tel: (0223) 420414
Document "POLYGONS SPS"     Category "SALES - Spec"
Document Issue 0.0 Tim Hartnall   30-Mar-1987
Document Issue 1.0 Tim Hartnall   06-Apr-1987
Document Issue 1.1 Tim Hartnall   23-Jun-1987
Document Issue 2.0 Tim Hartnall   15-Oct-1987
Document Issue 2.1 Adrian Cuthbert   19-Sep-1988
Document Issue 2.2 Simon Hancock   25-Mar-1991
Document Issue 2.3 Steve Townrow   30-Apr-1992
Document Issue 2.4 Paul Hardy   25-Feb-1994



The Laser-Scan IFF polygon processing package (POLYGONS) operates on Digital Equipment VAX, and Alpha AXP series computers running the VMS operating systems. See later sections for details of hardware and software prerequisites. It is recommended that the reader becomes familiar with the "LAMPS Environment Guide" which outlines in some detail the hardware and software environment required by the LAMPS package as a whole (of which POLYGONS is but a part). LAMPS is the *Laser-Scan *Automated *Map *Production *System.

IFF stands for *Internal *Feature *Format and is the Laser-Scan vector file format generated by LASERAID and other Laser-Scan mapping systems and used as the data structure throughout the Laser-Scan LAMPS system. IFF files are binary and cannot be manipulated directly using a text editor. The POLYGONS package enables the user to create and manipulate polygon data within IFF files.

The POLYGONS package consists of independent modules which together form a powerful polygon creation and manipulation system within an automated mapping or GIS (Geographical Information System) environment.

The POLYGONS package is designed for use in conjunction with the STRUCTURE package module ILINK. ILINK is used to provide link-node data structure within IFF files which is then used by the POLYGONS module IPOLYGON to form polygons. (See the STRUCTURE package SPS for details of LINK and the "IFF User Guide" for details of IFF link-node strructure).

All the POLYGONS modules have common command syntax which is decoded using the Command Line Interpreter as used by the VMS utilities. POLYGONS modules all generate VMS format messages and set VMS DCL symbol $STATUS on image exit. In command files the success of a preceding POLYGONS module may be tested using $STATUS before proceeding.

All POLYGONS modules are comprehensively documented in the "POLYGONS User Reference Manual" and the documentation includes an explanation of messages output by the modules together with suggested user action. POLYGONS is supplied with on-line help which is available via the VMS HELP utility.

POLYGONS is compatible with the 'new' type of IFF files produced by the Laser-Scan IMP (IFF MAP Processing) package. (For a detailed description of IFF types and their component entries see the "IFF User Guide").

Within the VMS system IFF files can be treated as any other file type for file management purposes. To enable the user to distinguish an IFF file from a file of another type IFF files have by default the file extension '.IFF', and link-node structured IFF files the extension '.IFJ'. To provide great flexibility in the production environment IFF files are referenced by all the POLYGONS modules using logical name LSL$IF:. (For an explanation of logical names see the VMS document set). Logical name LSL$IF: is assigned to a device and directory specification either using the VMS DEFINE command or the Laser-Scan SI utility.


The facilities offered by POLYGONS are described by module in alphabetical order of module.



The following computer hardware requirements are needed to run POLYGONS.


POLYGONS modules run under OpenVMS Version 5.5-2 or OpenVMS AXP V1.5 (or later versions) and assume upwards compatibility by DEC. POLYGONS modules may be run concurrently with other interactive and batch processes.

The prerequisite Laser-Scan STRUCTURE module ILINK provides the link/node data structure required by POLYGONS module IPOLYGON.

The prerequisite Laser-Scan MAPPING package provides IFF and FRT file interface libraries.

The Laser-Scan LITES2 interactive digitising and editing software is recommended for digitising vector input data. The Laser-Scan LASERAID automated digitising system is recommended for large numbers of input documents.

It is recommended that the reader becomes familiar with the LAMPS Environment Guide which outlines in greater detail the hardware and software environment required by the LAMPS package as a whole (of which POLYGONS is but a part).


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.


The POLYGONS module IPOLYGON can only be used in conjunction with the STRUCTURE package module ILINK.

ILINK enables "idealisation" of IFF geometry, and/or the creation of IFF link-node structure from unstructured IFF data. It is this latter ILINK feature which is required by IPOLYGON.

The main functions of ILINK are:

Each process uses working link to node and node to link pointers in the course of its operation, incorporating every junction detected. This structure can be discarded or retained in whole or in part in the IFF output. The options are as follows: Like IPOLYGON, ILINK is non-interactive and uses no graphics devices. A progress display can be activated for the more time consuming operations when the program is run in interactive mode. All warning messages and a summary of process statistics are written to SYS$OUTPUT.

For more information on ILINK please see the separate STRUCTURE Software Product Specification (SPS).


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