Roger André wrote:
Hi All,
I'd like to know if I can take the results of a MapServer Python
mapscript 'mapImage.getBytes()' operation, and feed it into GDAL as a
data source for an in-memory raster? The MapServer docs state that the
results of 'getBytes' in Python is a "string of binary data". I'm not
sure if GDAL can open this sort of object though.
For background purposes, the reason I would like to do this is so that I
can try replacing PIL with GDAL in TileCache for the cutting of
metatiles. PIL isn't properly saving the image formats generated by
MapServer, whereas GDAL replicates them perfectly.
Roger,
I am not aware of a way to utilize a raw buffer as a mem dataset from
Python (though this is doable from C++). However, you can just write
the buffer to a mem dataset. This code snippet from the autotest suite
shows something like this:
#######################################################
# Setup dataset
drv = gdal.GetDriverByName('MEM')
gdaltest.mem_ds = drv.Create( 'mem_1.mem', 50, 3, gdal.GDT_Int32, 1 )
ds = gdaltest.mem_ds
raw_data = array.array('f',list(range(150))).tostring()
ds.WriteRaster( 0, 0, 50, 3, raw_data,
buf_type = gdal.GDT_Float32,
band_list = [1] )
It is slightly more tricky with what I assume is a pixel interleaved 3
band image you would have. Without having tested it, something like this
might work:
mem_ds = gdal.GetDriverByName('MEM').Create('x',200,300,gdal.GDT_Byte,3)
mem_ds.WriteRaster( 0, 0, 200, 300,
mapImage.getBytes(), 200, 300, gdal.GDT_Byte,
band_list=[1,2,3],
buf_pixel_space=3,
buf_line_space=3*200,
buf_band_space=1)
Good luck,
--
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I set the clouds in motion - turn up | Frank Warmerdam, warmer...@pobox.com
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and watch the world go round - Rush | Geospatial Programmer for Rent
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