Changes between Initial Version and Version 3 of Ticket #515


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Timestamp:
Apr 2, 2007, 9:34:39 PM (17 years ago)
Author:
warmerdam
Comment:

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  • Ticket #515 – Description

    initial v3  
    1 {{{
    21OGRGeometry Intersect method does not work correctly in a geographic
    3 coordinate system (lat/lon coordinates), because it does not account for
    4 periodicity (i.e. "wrap-around" of lon-coordinate at dateline).
     2coordinate system (lat/lon coordinates), because it does not account for periodicity (i.e. "wrap-around" of lon-coordinate at dateline).
    53 
    6 OGRGeometry already has an associated spatial reference (with the method
    7 IsGeographic()). However, a remaining problem is that polygon edges are not
    8 well-defined in such a coordinate system (although the shortest connection is
    9 probably a reasonable assumption).
    10  
     4OGRGeometry already has an associated spatial reference (with the method IsGeographic()). However, a remaining problem is that polygon edges are not well-defined in such a coordinate system (although the shortest connection is probably a reasonable assumption).
     5
     6{{{
    117As a test case:
    12  
     8
    1391) download & tar xzf the following wrs2 zone definition file:
    1410ftp://ftp.glcf.umiacs.umd.edu/www/shapefile/wrs2.tar.gz
    15  
     11
    16122) execute 'ogrinfo -al wrs2.shp -spat 42 42 44 44'
    1713 
    18 ogrinfo will wrongly report wrs2 zones crossing the dateline, because the
    19 intersection routines' min-max check inverts the longitudal extent of these
    20 cells.
    21 }}}
     14ogrinfo will wrongly report wrs2 zones crossing the dateline, because the intersection routines' min-max check inverts the longitudal extent of these cells.