Laser-Scan Ltd.

Software Product Specification

IMP package

For LAMPS V4.4
Copyright (C) $$year Laser-Scan Ltd
Science Park, Milton Road, Cambridge, England CB4 4FY  tel: +44 (0) 1223 420414
Document "IMP SPS"     Category "SALES - Spec"
Document Issue 1.0 Tim Hartnall   10-Sep-1986
Document Issue 1.1 Tim Hartnall   30-Sep-1986
Document Issue 1.2 Tim Hartnall   30-Oct-1986
Document Issue 1.3 Tim Hartnall   18-Nov-1986
Document Issue 1.4 Tim Hartnall, Jon Billing 17-Nov-1987
Document Issue 2.0  Tim Hartnall                    14-Jan-1988
Document Issue 2.1  Sunil Gupta                     06-Jun-1991
Document Issue 2.2  Steve Townrow                   13-Jun-1991
Document Issue 2.3  Steve Townrow                   30-Apr-1992
Document Issue 2.4  Ron Russell    4-Mar-1993
Document Issue 2.5  Jon Barber   10-Aug-1994
Document Issue 2.6  Paul Hardy   19-Aug-1994



The Laser-Scan IFF Map Processing (IMP) package consists of independent modules which together form a powerful data manipulation system within an automated mapping environment. All the modules have common command syntax which is decoded using the Command Line Interpreter as used by the VAX/VMS utilities. IMP modules all generate VMS format messages and set VMS DCL symbol $STATUS on image exit. In command files the success of a preceding IMP module may be tested using $STATUS before proceeding. All IMP modules are comprehensively documented in the IMP Reference Manual and the documentation includes an explanation of messages output by the modules together with suggested user action. All IMP modules handle IFF HI (HIstory), ZS (three dimensional strings), TS (Text Status), CB (coordinate block) and type 2 MD (Map Descriptor) entries. (For a detailed description of these and the other IFF entries see the IFF Users Guide). These entries could not be handled by the DAMP (DAta &Manipulation &Package) utilities which IMP was designed to replace. IMP is supplied with on-line help which is available via the VMS HELP utility.


Four new IFF entry types are available for use with IMP programs.

Date Time Username Program Function Elapsed CPU STATUS 23-JUL-1986 12:22 CLARKE IMERGE Merge: rest 1:31:34 00:09:05 00000001

  • MD (type 2 Map Descriptor) entry, upwards compatible with the existing type 1 MD. This entry contains projection, scale and spheroid information etc. It also contains an origin offset. This is an (X,Y) coordinate pair, each held as a REAL*8 (double precision) number, that is added to any pair of coordinates in the IFF file to give the true projection coordinates of the points. This allows the absolute size of the coordinates in the IFF file, which are only held as REAL*4 (single precision) numbers to be reduced, thus avoiding problems of truncation and reduced accuracy.
  • TS (Text Status) entry. In the past IFF text features could contain only one text string, with associated location and descriptive data. With the introduction of the IFF TS entry text features may be composite - that is composed of several sub-texts or text components, which may be manipulated independently or as a single entity.
  • ZS (3 dimensional string) entry. The ZS 3 dimensional strings are held as x,y,z coordinates in a similar fashion to the existing IFF 2 dimensional ST (STring) entries.
  • CB (Coordinate Block) entry. In January 1988 the CB entry was introduced to replace the functionality of ST and ZS entries and offer the description of per-point attributes in addition to the X,Y and Z coordinates.


    IMP is designed to replace the existing Laser-Scan DAMP (DAta Manipulation Package). The following summary listing of the DAMP package can be made to indicate the functional corresponence between the two packages.

    | REPLACED       | DAMP MODULE FUNCTION                          | NEW IMP     |
    | DAMP MODULE    |                                               |
    | CHKLP          | Check for loops in IFF data                   | ICHECK      |
    | CMPIFF         | Compare two IFF files                         | IDIFFERENCE |
    | I2TEXT                                                         | ITOTEXT     |
    | and TEXT2I     | IFF/text file conversion (both ways)          | IFROMTEXT   |
    | ICE            | IFF combine and extract (for edge matching)   | IMERGE      |
    | ICLIP          | Map clipping                                  | IWINDOW     |
    | IED            | IFF patch editor                              | IPATCH      |
    | IFINFO         | Summarise the contents of an IFF file         | IINFO       |
    | IFIX           | Correct specific faults in IFF data           | IFIXAREA    |
    | IFSN           | Reallocate feature serial numbers             | IRENUMBER   |
    | IFT            | Tidy up an incomplete IFF file                | IMEND       |
    | IPR            | Process (transform or clip) IFF data          | ITRANS      |
    | IRN            | Reallocate internal sequence numbers          | IRENUMBER   |
    | LIT            | Change or extract feature codes within layers | ILAYFC      |
    | MER            | Merge IFF files or extract IFF layers         | IMERGE      |
    | MIF            | Mend an improperly closed IFF file            | IMEND       |
    | SCI            | Scan an IFF file, giving statistics           | IINFO       |
    | SELAC          | Select features on the basis of ACs or FSNs   | ISELAC      |
    | SIF            | Sort on FSN, ISN or FC		         | ISORT       |

    This list may be compared with the IMP package details in the following section. All major DAMP package functionality is retained in IMP, although the module which provides that functionality may have changed. In addition IMP offers many more functions than the DAMP package.


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