Bug report #3348
GDAL TIFF dataset masking not fully supported
| Status: | Closed | ||
|---|---|---|---|
| Priority: | Low | ||
| Assignee: | - | ||
| Category: | Rasters | ||
| Affected QGIS version: | 2.2.0 | Regression?: | No |
| Operating System: | All | Easy fix?: | No |
| Pull Request or Patch supplied: | No | Resolution: | fixed/implemented |
| Crashes QGIS or corrupts data: | No | Copied to github as #: | 13408 |
Description
recent improvements in masking of TIFF by GDAL can generate images that QGis does not completely support. Improved support would understand the masks and render only non-masked pixels. note that mapserver trunk understands this masking right now..
Related issues
History
#1
Updated by Alexander Bruy about 13 years ago
- Pull Request or Patch supplied set to No
- Status changed from Open to Closed
- Assignee deleted (
nobody -) - Resolution set to duplicate
Duplicate #2491
#2
Updated by Benjamin Schepers over 10 years ago
- Affected QGIS version set to 2.2.0
- Crashes QGIS or corrupts data set to No
- Target version changed from Version 1.7.0 to Version 2.2
- Status changed from Closed to Reopened
Internal NoData-Masks in GeoTIFFs seem not to be respected by QGIS. The masked area is shown black (Value "0,0,0") and not transparent ("NoData") as it should.
Internal NoData-Masks are possible since GDAL 1.6.0 --> http://www.gdal.org/frmt_gtiff.html
Use-Case are large aerial images (BigTIFFs with JPEG-Compression and internal tiles, internal pyramids an nodata-masks for all layers) with non-rectangle borders/masks (because of administrative borders, which - of course - don't respect classic rectangle BBOXes). Many of those large images (50+) should be shown patched together; this works flawlessly and with a not too big performance-hit in mapserver (and also ArcGIS :-( ).
WORKAROUND: the internal nodata-mask could be mapped to the alpha-channel with the use of gdal_translate and a VRT.
gdal_translate -b 1 -b 2 -b 3 -b mask -of VRT $SOURCE.tif $TARGET.vrt
After adding the VRT to QGIS, there is the possibility to select the new "channel 4" as transparency-channel.
IMHO a BUGFIX or "general" nodata-mask-support would be more performant and satisfying...
EDIT: Refering to #6360 there could be another checkbox "nodata-value from internal mask"?
#3
Updated by Jürgen Fischer over 10 years ago
- Target version changed from Version 2.2 to Future Release - Lower Priority
#4
Updated by Giovanni Manghi over 7 years ago
- Regression? set to No
- Easy fix? set to No
#5
Updated by Even Rouault about 7 years ago
- Status changed from Reopened to Closed
- Resolution changed from duplicate to fixed/implemented
Was implemented per 0f16eb869cf5efbce531fcb617aab36d09755306 in QGIS 3