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How To: Create the polygon coverage which is necessary to export a point coverage using SDTSEXPORT

Summary

The SDTSEXPORT command requires that a polygon coverage be provided which represents the bounding extent of the points being exported. This article provides the sequence of steps necessary to create the polygon coverage.

Procedure

This procedure will create a polygon coverage called BOUNDINGBOX which represents the extent of a point coverage called CITIES.

  1. Describe the CITIES point coverage, making note of the XMIN, YMIN, XMAX and YMAX coordinates.

    Code:
    Arc: describe cities
    Description of DOUBLE precision coverage cities

    FEATURE CLASSES

    Number of Attribute Spatial
    Feature Class Subclass Features data (bytes) Index? Topology?
    ------------- -------- --------- ------------ ------- ---------
    POINTS 22 110

    SECONDARY FEATURES

    Tics 4

    TOLERANCES

    Fuzzy = 0.002 N Dangle = 0.000 N

    COVERAGE BOUNDARY

    Xmin = 18.430 Xmax = 39.688
    Ymin = 40.630 Ymax = 52.245


  2. Use the GENERATE command to create a polygon coverage called BOUNDINGBOX which uses the XMIN, YMIN, XMAX and YMAX values of the point coverage.

    Code:
    Arc: precision double double

    Arc: generate boundingbox
    Copyright (C) 1982-2002 Environmental Systems Research Institute, Inc.
    All rights reserved.
    GENERATE 8.3 (Wed Dec 18 08:17:08 PST 2002)

    Generate: polygon
    Enter polygons.
    Terminate Polygons by entering END at X,Y: prompt.
    Terminate input by entering END at ID,X,Y: prompt.

    ID, {AUTO | X,Y}: 100
    X,Y: 18.430,40.630
    X,Y: 39.688,40.630
    X,Y: 39.688,52.245
    X,Y: 18.430,52.245
    X,Y: 18.430,40.630
    X,Y:
    (Label for ID 100 placed at 29.059,47.154)

    ID, {AUTO | X,Y}:
    Generate: quit

  3. BUILD the BOUNDINGBOX coverage.

    Code:
    Arc: build boundingbox poly
    Building polygons...

  4. Copy the projection definition from the point coverage to the polygon coverage.

    Code:
    Usage: PROJECTCOPY <COVER | GRID | FILE | TIN> <source>
    <COVER | GRID | FILE | TIN> <target>
    Arc: projectcopy cover cities cover boundingbox


    Note:
    Topological Vector Profile (TVP) is a subset of the Spatial Data Transfer Standard (SDTS), and TVP only allows the following external reference systems and units. If the data is in any other coordinate system than those listed below, the coverage must be projected before running SDTSEXPORT.


    GEO  - Lat/Long   GEOGRAPHIC          /* Geographic (latitude and longitude)
    SPCS - meters STATEPLANE /* State Plane Coordinate Systems
    UTM - meters UTM /* Universal Transverse Mercator
    UPS - meters UPSTEREOGRAPHIC /* Universal Polar Stereographic

  5. Use SDTSEXPORT to export the point coverage CITIES using the BOUNDINGBOX polygon coverage as the <in_dataset>.

    Code:
    Usage: SDTSEXPORT <TVP | POINT | RASTER> <in_dataset> <out_transfer_prefix>
    {in_point_cover} {out_DD_transfer} {Conv_Ctrl_File}
    Arc: sdtsexport tvp boundingbox suf1 cities