Opened 12 years ago
Last modified 12 years ago
#4211 assigned defect
Layer processing directive RESAMPLING and OFFSITE definition
Reported by: | armin | Owned by: | warmerdam |
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Priority: | normal | Milestone: | |
Component: | GDAL Support | Version: | 6.0 |
Severity: | normal | Keywords: | |
Cc: |
Description
The raster layer processing directive like
PROCESSING "RESAMPLE=BILINEAR"
causes some strange effects along the border of DATA-NODATA pixels for the resampling types "bilinear" and "average", but not for "nearest", when the NODATA pixels defined as not displayed/transparent via the map file tag
OFFSITE 0 0 0
This happens only when this border is not along an exact horizontal or vertical line but having an oblique, staircase-shaped borderline (typically the case for warped/rotated images images after reprojection with larger triangular border areas with NODATA).
This happened for GeoTIFF files, with or without overviews. Images were separate tiff images, used via TILEINDEX in MS layers, like
LAYER NAME "test_fc" TYPE Raster TILEINDEX "/home/test/tileindex" TILEITEM "location" DUMP TRUE METADATA "ows_title" "TEST, FALSE COLOR" END OFFSITE 0 0 0 PROCESSING "RESAMPLE=BILINEAR" PROJECTION "init=epsg:3035" END END
The images are correctly pixel-aligned to each other, i.e. having the same grid geometry.
The attached screenshots show the effects.
Software versions used were MS 6.0.1, GDAL 1.9, OS Linux 64bit.
Attachments (3)
Change History (5)
by , 12 years ago
Attachment: | wms_resampling-bilinear_02.png added |
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by , 12 years ago
Attachment: | wms_resampling-bilinear.png added |
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by , 12 years ago
Attachment: | wms_resampling-nearest.png added |
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comment:1 by , 12 years ago
Status: | new → assigned |
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comment:2 by , 12 years ago
yes, this issue seems not to be related to any overviews.
I will prepare 2 or 3 clipped out images and the map file.
I am going to need a mapfile, mapdata and shp2img command that demonstrates the issue.
I gather you found the problem was *not* related to overview generation in GDAL, right?