| Ah, so zoom levels are already in the geotiff. I thought they were based on resolution. That was by the way the whole gdalinfo I printed, so I guess the one who made the tiff hasn't added zoom levels?
Regards /Per
 Per Ohlson, M.Sc. E.E. Stockholm/Gothenburg, Sweden
Le lundi 21 janvier 2013 20:15:42, Per Ohlson a écrit :
Hi,
I have two different geotiff-charts which have the same number of pixels,
and similar information when viewing in gdalinfo, but one misbehaves while
tiling.
For the problem chart, only the zoom levels 0-6 are tiled, but for the
correctly handled chart, zoom levels 4-11 are tiled. Both are around
23000x15000 pixels and 72 dpi.
So, what decides the zoom levels? I thought it was pixels and dpi..
You probably don't give the whole context. From the gdalinfo output, I can
tell that none of your geotiffs are tiled, or have overviews (precomputed zoom
levels). So this may depend on the application that make use of them.
gdalinfo on the working chart gives:
Coordinate System is:
Size is 15108, 23181
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 = (167.635052101782918,-27.435225354710909)
Pixel Size = (0.000619744987014,-0.000517525434692)
Metadata:
AREA_OR_POINT=Area
Image Structure Metadata:
COMPRESSION=LZW
INTERLEAVE=PIXEL
Corner Coordinates:
Upper Left ( 167.6350521, -27.4352254) (167d38' 6.19"E, 27d26' 6.81"S)
Lower Left ( 167.6350521, -39.4319825) (167d38' 6.19"E, 39d25'55.14"S)
Upper Right ( 176.9981594, -27.4352254) (176d59'53.37"E, 27d26' 6.81"S)
Lower Right ( 176.9981594, -39.4319825) (176d59'53.37"E, 39d25'55.14"S)
Center ( 172.3166057, -33.4336039) (172d18'59.78"E, 33d26' 0.97"S)
Band 1 Block=15108x1 Type=Byte, ColorInterp=Red
Mask Flags: PER_DATASET ALPHA
Band 2 Block=15108x1 Type=Byte, ColorInterp=Green
Mask Flags: PER_DATASET ALPHA
Band 3 Block=15108x1 Type=Byte, ColorInterp=Blue
Mask Flags: PER_DATASET ALPHA
Band 4 Block=15108x1 Type=Byte, ColorInterp=Alpha
gdalinfo on the problem chart gives:
Size is 15319, 23593
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 = (176.502369113268770,-25.635284667174400)
Pixel Size = (0.000619910224237,-0.000526829594898)
Metadata:
AREA_OR_POINT=Area
Image Structure Metadata:
COMPRESSION=LZW
INTERLEAVE=PIXEL
Corner Coordinates:
Upper Left ( 176.5023691, -25.6352847) (176d30' 8.53"E, 25d38' 7.02"S)
Lower Left ( 176.5023691, -38.0647753) (176d30' 8.53"E, 38d 3'53.19"S)
Upper Right ( 185.999, -25.635) (185d59'55.59"E, 25d38' 7.02"S)
Lower Right ( 185.999, -38.065) (185d59'55.59"E, 38d 3'53.19"S)
Center ( 181.251, -31.850) (181d15' 2.06"E, 31d51' 0.11"S)
Band 1 Block=15319x1 Type=Byte, ColorInterp=Red
Mask Flags: PER_DATASET ALPHA
Band 2 Block=15319x1 Type=Byte, ColorInterp=Green
Mask Flags: PER_DATASET ALPHA
Band 3 Block=15319x1 Type=Byte, ColorInterp=Blue
Mask Flags: PER_DATASET ALPHA
Band 4 Block=15319x1 Type=Byte, ColorInterp=Alpha
Regards
/Per
Per Ohlson, M.Sc. E.E.
Nanight AB - http://www.nanight.se
Stockholm/Gothenburg, Sweden
[email protected]
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