On lundi 6 mars 2017 13:20:50 CET Stephen Woodbridge wrote:
Hi,
I have a collection of doqqs that look like the two below. I trying to
extract a small image the crosses between the two doqqs, but I'm getting
a black line between them. When I serve them via mapserver, I'm not
getting this.
gdalbuildvrt -addalpha tmp-tc-13110.vrt m_4012408_sw_10_h_20160528.tif
m_4012416_nw_10_h_20160528.tif
gdal_translate -of GTiff -outsize 1360 1360 -projwin -124.083968798
40.8779687978 -124.076031202 40.8700312022 -co TILED=YES -co
COMPRESS=JPEG -co JPEG_QUALITY=90 --config GDAL_TIFF_INTERNAL_MASK YES
tmp-tc-13110.vrt oaf2-tc.tif
I get the same result regardless of the -addalpha in the gdalbuildvrt
command.
What am I missing?
If your tiles have colar (which I supposed since they have a mask),
gdalbuildvrt (actually the VRT driver) doesn't take it into account as
you might expect. It doesn't blend alpha/mask, but takes the alpha/mask
value of the last source in the VRT that intersects the window of
interest. You might have more success with
gdalwarp in1.tif in2.tif out.tif -dstalpha -te xmin ymin xmax ymax
-Steve
$ gdalinfo m_4012408_sw_10_h_20160528.tif
Driver: GTiff/GeoTIFF
Files: m_4012408_sw_10_h_20160528.tif
Size is 11140, 10847
Coordinate System is:
GEOGCS["WGS 84",
DATUM["WGS_1984",
SPHEROID["WGS 84",6378137,298.257223563,
AUTHORITY["EPSG","7030"]],
AUTHORITY["EPSG","6326"]],
PRIMEM["Greenwich",0],
UNIT["degree",0.0174532925199433],
AUTHORITY["EPSG","4326"]]
Origin = (-124.127892543854088,40.939476459321497)
Pixel Size = (0.000006127013352,-0.000006127013352)
Metadata:
AREA_OR_POINT=Area
Image Structure Metadata:
COMPRESSION=YCbCr JPEG
INTERLEAVE=PIXEL
SOURCE_COLOR_SPACE=YCbCr
Corner Coordinates:
Upper Left (-124.1278925, 40.9394765) (124d 7'40.41"W, 40d56'22.12"N)
Lower Left (-124.1278925, 40.8730167) (124d 7'40.41"W, 40d52'22.86"N)
Upper Right (-124.0596376, 40.9394765) (124d 3'34.70"W, 40d56'22.12"N)
Lower Right (-124.0596376, 40.8730167) (124d 3'34.70"W, 40d52'22.86"N)
Center (-124.0937651, 40.9062466) (124d 5'37.55"W, 40d54'22.49"N)
Band 1 Block=256x256 Type=Byte, ColorInterp=Red
Overviews: 5570x5424, 2785x2712, 1393x1356, 697x678, 349x339,
175x170, 88x85
Mask Flags: PER_DATASET
Overviews of mask band: 5570x5424, 2785x2712, 1393x1356, 697x678,
349x339, 175x170, 88x85
Band 2 Block=256x256 Type=Byte, ColorInterp=Green
Overviews: 5570x5424, 2785x2712, 1393x1356, 697x678, 349x339,
175x170, 88x85
Mask Flags: PER_DATASET
Overviews of mask band: 5570x5424, 2785x2712, 1393x1356, 697x678,
349x339, 175x170, 88x85
Band 3 Block=256x256 Type=Byte, ColorInterp=Blue
Overviews: 5570x5424, 2785x2712, 1393x1356, 697x678, 349x339,
175x170, 88x85
Mask Flags: PER_DATASET
Overviews of mask band: 5570x5424, 2785x2712, 1393x1356, 697x678,
349x339, 175x170, 88x85
$ gdalinfo m_4012416_nw_10_h_20160528.tif
Driver: GTiff/GeoTIFF
Files: m_4012416_nw_10_h_20160528.tif
Size is 11145, 10851
Coordinate System is:
GEOGCS["WGS 84",
DATUM["WGS_1984",
SPHEROID["WGS 84",6378137,298.257223563,
AUTHORITY["EPSG","7030"]],
AUTHORITY["EPSG","6326"]],
PRIMEM["Greenwich",0],
UNIT["degree",0.0174532925199433],
AUTHORITY["EPSG","4326"]]
Origin = (-124.127899397118711,40.876995871942221)
Pixel Size = (0.000006124881549,-0.000006124881549)
Metadata:
AREA_OR_POINT=Area
Image Structure Metadata:
COMPRESSION=YCbCr JPEG
INTERLEAVE=PIXEL
SOURCE_COLOR_SPACE=YCbCr
Corner Coordinates:
Upper Left (-124.1278994, 40.8769959) (124d 7'40.44"W, 40d52'37.19"N)
Lower Left (-124.1278994, 40.8105348) (124d 7'40.44"W, 40d48'37.93"N)
Upper Right (-124.0596376, 40.8769959) (124d 3'34.70"W, 40d52'37.19"N)
Lower Right (-124.0596376, 40.8105348) (124d 3'34.70"W, 40d48'37.93"N)
Center (-124.0937685, 40.8437653) (124d 5'37.57"W, 40d50'37.56"N)
Band 1 Block=256x256 Type=Byte, ColorInterp=Red
Overviews: 5573x5426, 2787x2713, 1394x1357, 697x679, 349x340,
175x170, 88x85
Mask Flags: PER_DATASET
Overviews of mask band: 5573x5426, 2787x2713, 1394x1357, 697x679,
349x340, 175x170, 88x85
Band 2 Block=256x256 Type=Byte, ColorInterp=Green
Overviews: 5573x5426, 2787x2713, 1394x1357, 697x679, 349x340,
175x170, 88x85
Mask Flags: PER_DATASET
Overviews of mask band: 5573x5426, 2787x2713, 1394x1357, 697x679,
349x340, 175x170, 88x85
Band 3 Block=256x256 Type=Byte, ColorInterp=Blue
Overviews: 5573x5426, 2787x2713, 1394x1357, 697x679, 349x340,
175x170, 88x85
Mask Flags: PER_DATASET
Overviews of mask band: 5573x5426, 2787x2713, 1394x1357, 697x679,
349x340, 175x170, 88x85
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