[gdal-dev] Neatline for USGS PDF maps

[Even Rouault]

Le samedi 19 janvier 2013 16:28:53, Even Rouault a écrit :
> Le samedi 19 janvier 2013 03:38:16, Eli Adam a écrit :
> > Checking over some USGS topo PDFs, the neatline reported appears too
> > large.  Has anyone else check this or noticed anything similar?
> > Specific details below.
> 
> Eli,
> 
> Looking more closely at those files, I see that there are various
> registration blocks. The algorithm up to now was to select the
> registration block whose neatline covered the most area in terms of
> pixels. In the case of
> OR_Newport_North_20110824_TM_geo.pdf, those blocks are :
> "UTM Grid and Projection"
> "Orthoimage"
> "Map Layers"
> "Adjoining Quadrangles Diagram"
> 
> The number and names of blocks may change, but in all USGS topo PDFs
> samples I've tried, the "Map Layers" is always present and seems to the
> one that lead to the best results, so I've just pushed a change to select
> it when it is found.
> 
> You can use the following Python script to automate fetching the neatline
> and launching gdalwarp to use it :
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> from osgeo import gdal
> import os
> import sys
> 
> ds = gdal.Open(sys.argv[1])
> neatline_wkt = ds.GetMetadataItem("NEATLINE")
> ds = None
> 
> f = open('cutline.csv', 'wt')
> f.write('id,WKT\n')
> f.write('1,"%s"\n' % neatline_wkt)
> f.close()
> 
> os.system('gdalwarp %s %s.tif ' % (sys.argv[1], sys.argv[1]) +
>           '-crop_to_cutline -cutline cutline.csv -overwrite')
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If you're interested in only the raster part, let's imagine that the above 
script is called cutline.py, you can try the following :

export GDAL_PDF_RENDERING_OPTIONS=RASTER
(or set GDAL_PDF_RENDERING_OPTIONS=RASTER on windows)

python cutline.py your.pdf

nearblack your.pdf -o your_rgba.pdf -of GTiff -setalpha -color 0,0,0 \
		-color 255,255,255

> 
> Best regards,
> 
> Even
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