Opened 15 years ago

Closed 5 years ago

#2729 closed enhancement (wontfix)

[PATCH] gdalwarp - Polar to Cylindrical reprojections cuts off part of target image when Polar image crosses pole

Reported by: glewis Owned by: Even Rouault
Priority: normal Milestone: closed_because_of_github_migration
Component: Utilities Version: 1.6.0
Severity: normal Keywords: gdalwarp
Cc: warmerdam


When using the gdalwarp tool, if converting an image in a Polar projection (such as an laea projection) that crosses the pole, to a Cylindrical projection (such as a latlong projection), by default the target image is cut off and doesn't extend to the pole.

Using -wo settings of SOURCE_EXTRA, SAMPLE_GRID, and SAMPLE_STEP do not change this behavior. Manually setting the cylindrical extent boundaries with -te does work, but since it is manual you have to know what values to use.

Allowing an option to force internal gridding would be beneficial.

Attachments (1)

gdaltransformer_bug2729.patch (6.9 KB ) - added by Even Rouault 15 years ago.

Download all attachments as: .zip

Change History (5)

comment:1 by Even Rouault, 15 years ago

Owner: changed from warmerdam to Even Rouault
Status: newassigned

comment:2 by Even Rouault, 15 years ago

Cc: warmerdam added
Summary: gdalwarp - Polar to Cylindrical reprojections cuts off part of target image when Polar image crosses pole[PATCH] gdalwarp - Polar to Cylindrical reprojections cuts off part of target image when Polar image crosses pole

Attached a patch that solves the issue.

With it: gdalwarp -t_srs EPSG:4326 polar.gtiff.tif polar_wgs84.tif


$ gdalinfo polar_wgs84.tif
Driver: GTiff/GeoTIFF
Files: polar_wgs84.tif
Size is 5111, 857
Origin = (-180.000000000000000,90.000000000000000)
Pixel Size = (0.070436313832909,-0.070445741950979)
Image Structure Metadata:
Corner Coordinates:
Upper Left  (-180.0000000,  90.0000000) (180d 0'0.00"W, 90d 0'0.00"N)
Lower Left  (-180.0000000,  29.6279991) (180d 0'0.00"W, 29d37'40.80"N)
Upper Right ( 180.0000000,  90.0000000) (180d 0'0.00"E, 90d 0'0.00"N)
Lower Right ( 180.0000000,  29.6279991) (180d 0'0.00"E, 29d37'40.80"N)
Center      (  -0.0000000,  59.8139996) (  0d 0'0.00"W, 59d48'50.40"N)
Band 1 Block=5111x1 Type=UInt16, ColorInterp=Gray

There's one part where I'd like to get Frank's opinion. It's the part where I adjust the x and y resolution so that the computed geotransform with the computed width and height doesn't overlap the 180° meridian. The only issue I see with that is that the pixel size is no longer a perfect square, as it's stated in the documentation of GDALSuggestedWarpOutput2(). But otherwise, another patch I'm working on in GDALWarpOperation::ComputeSourceWindow() for dealing with the inverse problem (warping to polar projection) can't work properly if the right edge of the image overlaps the 180° meridian.

by Even Rouault, 15 years ago

comment:3 by warmerdam, 12 years ago

Milestone: 1.6.4

Remove non-serious milestone.

comment:4 by Even Rouault, 5 years ago

Milestone: closed_because_of_github_migration
Resolution: wontfix
Status: assignedclosed

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