>From my mail to geowankers:
gdalinfo $i|grep NEATLINE | awk -F= '{print "foo,WKT\nbla,\"" $2 "\""}' >
$i.csv;
gdalwarp -crop_to_cutline -cutline $i.csv -co "GDAL_PDF_DPI=250" -of GTiff
$i $i.tiff
On Tue, Dec 13, 2011 at 1:58 PM, Smith, Michael <[email protected]>wrote:
> **
> I am trying to convert the historic USGS topo maps (GeoPDFs) into GeoTIFFs
> with GDAL 1.8 . A very straightforward thing to do is
>
> gdal_translate in.pdf out.tiff
>
> This works fine but the TIFF looks as if the PDF was exported at 150dpi,
> which is a pretty crappy resolution. Using something else (like PDFCreator
> and printing to a TIFF), the USGS GeoPDFs can be exported at higher
> resolutions, but then of course you lose the georeferencing. So I have
> GDAL which keeps the georeferencing but only seems to like 150dpi, and then
> a zillion other solutions which allow 300 dpi or 600 dpi, but have no
> georeferencing.
>
> I did try gdalwarp -tr 5 5 for example (which would roughly be equivalent
> to one of these maps at 300dpi), but it is clear that it is still rendering
> the PDF at 150dpi and then generating a 5-meter TIFF - looks no different
> really than the default output with gdal_translate.
>
> Is there some argument that would specify the dpi at which the GeoPDF were
> rendered before conversion to GeoTIFF? I don't see anything like that in
> the docs or the list archives.
>
> BTW if you haven't checked out the historic topos they are great, going
> back to the 1880s for Maine. What fun!
>
> My ultimate goal is to have a seamless mosaic WMS of the old topos for
> Maine.
>
> *****************
> Michael Smith
> State GIS Manager, Maine Office of GIS, Maine OIT
> Board Member, Maine GeoLibrary
> Board Member, Maine GIS Users Group
> State Rep, National States Geographic Information Council
>
> [image: icons]
>
> State House Station 174
> 264 Civic Center Drive
> Augusta, ME 04333-0174
> (207) 215-5530
>
> 69 o 47' 49.5"W 44 o 20' 54.5"N
>
>
>
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>
--
Derrick
<<icons_tiny.jpg>>
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