Opened 11 years ago

Closed 4 years ago

#4301 closed defect (wontfix)

Gdal_contour can make topologically incorrect vectors

Reported by: ysid Owned by: warmerdam
Priority: normal Milestone: closed_because_of_github_migration
Component: default Version: 1.8.0
Severity: normal Keywords:
Cc: abarton

Description

When gdal_contour is used to generate contours, and then these contours are clipped using ogr2ogr, a message regarding a topology exception may occur. Here is a capture of an example where this occurs:

gdal_contour -b 1 -a elevation -snodata -999999 -i 500 -off 1e-005 input.tif Acontours_500.shp
0...10...20...30...40...50...60...70...80...90...100 - done.

ogr2ogr.exe -select elevation -clipsrc 0 -90 90 0 Bcontours_500.shp Acontours_500.shp
ERROR 1: TopologyException: found non-noded intersection between LINESTRING (42.1792 -0.829167, 42.1
875 -0.8375) and LINESTRING (42.1875 -0.8375, 42.1875 -0.8375) at 42.1875 -0.8375
ERROR 1: TopologyException: found non-noded intersection between LINESTRING (42.0292 -1.00417, 42.03
75 -1.0125) and LINESTRING (42.0375 -1.0125, 42.0375 -1.0125) at 42.0375 -1.0125
ERROR 1: TopologyException: found non-noded intersection between LINESTRING (8.84583 -0.829167, 8.84
583 -0.829167) and LINESTRING (8.84583 -0.829167, 8.84583 -0.829167) at 8.84583 -0.829167
ERROR 1: TopologyException: found non-noded intersection between LINESTRING (32.6375 -82.4958, 32.63
75 -82.4958) and LINESTRING (32.6375 -82.4958, 32.6375 -82.4958) at 32.6375 -82.4958

In this example, the error occurs at the zero contour on the coast of Africa. The entire contour around the coast is eliminated due to this error. The source file listed here is too large to attach, but can be provided to whoever works on this ticket.

Change History (2)

comment:1 by ysid, 11 years ago

Cc: abarton added

comment:2 by Even Rouault, 4 years ago

Milestone: closed_because_of_github_migration
Resolution: wontfix
Status: newclosed

This ticket has been automatically closed because Trac is no longer used for GDAL bug tracking, since the project has migrated to GitHub. If you believe this ticket is still valid, you may file it to https://github.com/OSGeo/gdal/issues if it is not already reported there.

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