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Re: Issue loading TIFF images with plugin/TIF [message #59535 is a reply to message #59526]

Wed, 18 January 2023 11:12

Tom1
Messages: 1302
Registered: March 2007

Ultimate Contributor

Hi,

Here's my latest tifupp.cpp. I have further fine tuned the GeoTIFF support.

- All meta data available through GeoKeys are now saved and available through GetMetaData() using key "GK*", e.g. "GK3072".
- TIFFTAG_ORIENTATION is stored as metadata (Key "tiff_orientation") for external normalization of orientation.
- The pixel_is_area == true is now default, as some rasters omit this GeoKey and normally behave as such. Only files including GeoKey for 'pixel_is_point' are treated as such and normalized to pixel_is_area style.
- TIFFTAG_GEOTIEPOINTS can now be accepted without TIFFTAG_GEOPIXELSCALE and geo_matrix can be solved from three such points
- TIFFTAG_GDAL_NODATA is now detected and added to metadata with key "nodata".
- FetchPage() tmpfile feature is disabled (to fix display of e.g. 1511geotiff.tif below)

Mirek, could you consider merging these changes?

I ended up normalizing the orientation in my program while reading the data scanline-by-scanline. This saves memory when processing extremely large GeoTIFFs.

Best regards,

Tom

EDIT: There is still something wrong here with the geo_matrix when generated from TIFFTAG_GEOTIEPOINTS without TIFFTAG_GEOPIXELSCALE, i.e. the tp_* files. (Some TIFF -orientations do not work right yet.) I will keep working on this...

EDIT2: OK, the geo_matrix mapping for all combinations seem to work correctly now. (Note that tp_* files with multiple geotiepoints are indeed rotated and should display exactly on top of each other.)

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[Updated on: Wed, 18 January 2023 16:25]

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