[Gvsig_english] Problem loading big raster file.

[Luis W. Sevilla]

Hi,
IMHO you're getting the expected behavior. As plain tiff is not a 
pyramid/tiled file format, gdal raster driver must parse almost the 
whole file, and even more, it must read *complete* all lines it's 
rendering, even if you're only seing 200 px wide, it needs to read the 
whole 10001.
You may try to convert the file into an ECW (that it's a pyramid and 
tiled format), and you'll see a boost in performance, at least 10 times 
faster.

hope it helps
    Luis

Wolfgang Qual wrote:
> Dear Manuel, Luis, list,
> the file is a tiff-file. See gdalinfo-output
>
> wolfgang.qual at rgu04-200:~$ gdalinfo 44655342.tif
> Driver: GTiff/GeoTIFF
> Files: 44655342.tif
> Size is 10001, 10001
> Coordinate System is:
> PROJCS[" Projection Name = Transverse Mercator Units = meters GeoTIFF Units
> = meters",
>     GEOGCS[" Unable to match Ellipsoid (Datum) to a GeographicTypeGeoKey
> value Ellipsoid = Bessel Datum = DE_DHDN (",
>         DATUM["unknown",
>             SPHEROID["unnamed",6377397.155,299.1528131060796]],
>         PRIMEM["Greenwich",0],
>         UNIT["degree",0.0174532925199433]],
>     PROJECTION["Transverse_Mercator"],
>     PARAMETER["latitude_of_origin",0],
>     PARAMETER["central_meridian",12],
>     PARAMETER["scale_factor",1],
>     PARAMETER["false_easting",4500000],
>     PARAMETER["false_northing",0],
>     UNIT["metre",1,
>         AUTHORITY["EPSG","9001"]]]
> Origin = (4464999.950000000186265,5343000.049999999813735)
> Pixel Size = (0.100000000000000,-0.100000000000000)
> Metadata:
>   AREA_OR_POINT=Area
>   TIFFTAG_SOFTWARE=IMAGINE TIFF Support
> Copyright 1991 - 1999 by ERDAS, Inc. All Rights Reserved
> @(#)$RCSfile: etif.c $ $Revision: 1.10.1.9.1.9.2.11 $ $Date: 2004/09/15
> 18:42:01EDT $
>   TIFFTAG_XRESOLUTION=1
>   TIFFTAG_YRESOLUTION=1
>   TIFFTAG_RESOLUTIONUNIT=1 (unitless)
> Image Structure Metadata:
>   INTERLEAVE=PIXEL
> Corner Coordinates:
> Upper Left  ( 4464999.950, 5343000.050) ( 11d31'43.97"E, 48d13'29.74"N)
> Lower Left  ( 4464999.950, 5341999.950) ( 11d31'44.27"E, 48d12'57.36"N)
> Upper Right ( 4466000.050, 5343000.050) ( 11d32'32.43"E, 48d13'29.94"N)
> Lower Right ( 4466000.050, 5341999.950) ( 11d32'32.72"E, 48d12'57.56"N)
> Center      ( 4465500.000, 5342500.000) ( 11d32'8.35"E, 48d13'13.65"N)
> Band 1 Block=10001x1 Type=Byte, ColorInterp=Red
> Band 2 Block=10001x1 Type=Byte, ColorInterp=Green
> Band 3 Block=10001x1 Type=Byte, ColorInterp=Blue
>
> Other files worked better, e.g. a larger ERDAS-rasterfile with internal
> overviews.
>
> Best,
> Wolfgang
>
>   


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