Travis, I am not aware of a good way to do this. What I do is create separate mask directories looking like te following. Note the "Subfile Type: transparency mask (4 = 0x4)" directories. It isn't clear that all applications will honor these, but modern GDAL treats this as a PER_DATASET mask, and modern GDAL using applications that honor this style of masking will support the mask properly. I think modern QGIS does for instance, and MapServer. I could do some digging for the GDAL script code that makes these if you like.
Best regards, Frank $ tiffinfo 20200708_082104_1002_Browse.tif TIFFReadDirectory: Warning, Unknown field with tag 33550 (0x830e) encountered. TIFFReadDirectory: Warning, Unknown field with tag 33922 (0x8482) encountered. TIFFReadDirectory: Warning, Unknown field with tag 34735 (0x87af) encountered. TIFFReadDirectory: Warning, Unknown field with tag 34737 (0x87b1) encountered. TIFFReadDirectory: Warning, Unknown field with tag 42112 (0xa480) encountered. TIFF Directory at offset 0x17794e (1538382) Image Width: 5870 Image Length: 2889 Tile Width: 256 Tile Length: 256 Bits/Sample: 8 Sample Format: unsigned integer Compression Scheme: JPEG Photometric Interpretation: YCbCr YCbCr Subsampling: 2, 2 Samples/Pixel: 3 Planar Configuration: single image plane Reference Black/White: 0: 0 255 1: 128 255 2: 128 255 ImageDescription: {"fp_center": [23.21221629852675, -19.107257323766635]} DateTime: 2020:07:08 08:21:04 Tag 33550: 4.777314,4.777314,0.000000 Tag 33922: 0.000000,0.000000,0.000000,2569932.323447,-2160669.364808,0.000000 Tag 34735: 1,1,0,7,1024,0,1,1,1025,0,1,1,1026,34737,25,0,2049,34737,7,25,2054,0,1,9102,3072,0,1,3857,3076,0,1,9001 Tag 34737: WGS 84 / Pseudo-Mercator|WGS 84| Tag 42112: <GDALMetadata> <Item name="DESCRIPTION" sample="0" role="description">red</Item> <Item name="DESCRIPTION" sample="1" role="description">green</Item> <Item name="DESCRIPTION" sample="2" role="description">blue</Item> </GDALMetadata> JPEG Tables: (142 bytes) TIFF Directory at offset 0xb6a (2922) Subfile Type: transparency mask (4 = 0x4) Image Width: 5870 Image Length: 2889 Tile Width: 256 Tile Length: 256 Bits/Sample: 1 Sample Format: unsigned integer Compression Scheme: AdobeDeflate Photometric Interpretation: transparency mask Samples/Pixel: 1 Planar Configuration: single image plane Predictor: none 1 (0x1) TIFF Directory at offset 0x14b8 (5304) Subfile Type: reduced-resolution image (1 = 0x1) Image Width: 1468 Image Length: 723 Tile Width: 128 Tile Length: 128 Bits/Sample: 8 Sample Format: unsigned integer Compression Scheme: JPEG Photometric Interpretation: YCbCr YCbCr Subsampling: 2, 2 Samples/Pixel: 3 Planar Configuration: single image plane Reference Black/White: 0: 0 255 1: 128 255 2: 128 255 JPEG Tables: (142 bytes) TIFF Directory at offset 0x1888 (6280) Subfile Type: reduced-resolution image (1 = 0x1) Image Width: 734 Image Length: 362 Tile Width: 128 Tile Length: 128 Bits/Sample: 8 Sample Format: unsigned integer Compression Scheme: JPEG Photometric Interpretation: YCbCr YCbCr Subsampling: 2, 2 Samples/Pixel: 3 Planar Configuration: single image plane Reference Black/White: 0: 0 255 1: 128 255 2: 128 255 JPEG Tables: (142 bytes) TIFF Directory at offset 0x1aa8 (6824) Subfile Type: reduced-resolution image (1 = 0x1) Image Width: 367 Image Length: 181 Tile Width: 128 Tile Length: 128 Bits/Sample: 8 Sample Format: unsigned integer Compression Scheme: JPEG Photometric Interpretation: YCbCr YCbCr Subsampling: 2, 2 Samples/Pixel: 3 Planar Configuration: single image plane Reference Black/White: 0: 0 255 1: 128 255 2: 128 255 JPEG Tables: (142 bytes) TIFF Directory at offset 0x1c68 (7272) Subfile Type: reduced-resolution image/transparency mask (5 = 0x5) Image Width: 1468 Image Length: 723 Tile Width: 128 Tile Length: 128 Bits/Sample: 1 Sample Format: unsigned integer Compression Scheme: AdobeDeflate Photometric Interpretation: transparency mask Samples/Pixel: 1 Planar Configuration: single image plane Predictor: none 1 (0x1) TIFF Directory at offset 0x1f56 (8022) Subfile Type: reduced-resolution image/transparency mask (5 = 0x5) Image Width: 734 Image Length: 362 Tile Width: 128 Tile Length: 128 Bits/Sample: 1 Sample Format: unsigned integer Compression Scheme: AdobeDeflate Photometric Interpretation: transparency mask Samples/Pixel: 1 Planar Configuration: single image plane Predictor: none 1 (0x1) TIFF Directory at offset 0x2094 (8340) Subfile Type: reduced-resolution image/transparency mask (5 = 0x5) Image Width: 367 Image Length: 181 Tile Width: 128 Tile Length: 128 Bits/Sample: 1 Sample Format: unsigned integer Compression Scheme: AdobeDeflate Photometric Interpretation: transparency mask Samples/Pixel: 1 Planar Configuration: single image plane Predictor: none 1 (0x1) On Tue, Jul 19, 2022 at 3:19 PM Travis Kirstine <traviskirst...@gmail.com> wrote: > I've been trying to create a COG with JPEG compression with transparent > nodata values without much success. Is this possible without creating a > secondary mask? > > Any hints? > > Regards > _______________________________________________ > gdal-dev mailing list > gdal-dev@lists.osgeo.org > https://lists.osgeo.org/mailman/listinfo/gdal-dev > -- ---------------------------------------+-------------------------------------- I set the clouds in motion - turn up | Frank Warmerdam, warmer...@pobox.com light and sound - activate the windows | +1 650-701-7823 and watch the world go round - Rush | Geospatial Software Developer
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