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Michael,<br>
<br>
GDAL's PDF format page says you can use the GDAL_PDF_DPI config
option...<br>
<pre class="moz-signature" cols="72">Best Regards,
Brent Fraser</pre>
<br>
On 12/13/2011 11:58 AM, Smith, Michael wrote:
<blockquote
cite="mid:4EFF8BB964547748A07CA32961810C041BD7D69D@SOM-TEAQASMAIL1.som.w2k.state.me.us"
type="cite">
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<div><span class="009512717-13122011"><font face="Arial" size="2">I
am trying to convert the historic USGS topo maps
(GeoPDFs) into GeoTIFFs<span class="543185718-13122011"><font
color="#0000ff"><font color="#000000"> with GDAL 1.8</font> </font></span>.
A very straightforward thing to do is</font></span></div>
<div><span class="009512717-13122011"></span> </div>
<div><span class="009512717-13122011"><font face="Arial" size="2">gdal_translate
in.pdf out.tiff</font></span></div>
<div><span class="009512717-13122011"></span> </div>
<div><span class="009512717-13122011"><font face="Arial" size="2">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.</font></span></div>
<div><span class="009512717-13122011"></span> </div>
<div><span class="009512717-13122011"><font face="Arial" size="2">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.</font></span></div>
<div><span class="009512717-13122011"></span> </div>
<span class="009512717-13122011">
<div><span class="009512717-13122011"><font face="Arial"
size="2">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.</font></span></div>
<div><span class="009512717-13122011"></span> </div>
<div><font face="Arial" size="2">BTW if you haven't checked out
the historic topos they are great, going back to the 1880s
for Maine. What fun!</font></div>
<div> </div>
<div><span class="009512717-13122011"><font face="Arial"
size="2">My ultimate goal is to have a seamless mosaic WMS
of the old topos for Maine.</font></span></div>
<div><span class="009512717-13122011"></span> </div>
<div dir="ltr" align="left">*****************<br>
<font size="-1"><span style="FONT-FAMILY: Arial">Michael Smith</span><br>
<span style="FONT-FAMILY: Arial">State GIS Manager, Maine
Office of GIS, Maine OIT</span><br>
<span style="FONT-FAMILY: Arial">Board Member, Maine
GeoLibrary</span><br>
<span style="FONT-FAMILY: Arial">Board Member, Maine GIS
Users Group</span><br>
<span style="FONT-FAMILY: Arial">State Rep, National States
Geographic Information Council<br>
<br>
</span></font><img alt="icons"
src="cid:part1.01080604.02020606@geoanalytic.com"
usemap="#iconsmap" border="0" height="68" width="299"> <map
name="iconsmap">
<area href="http://www.maine.gov/megis" shape="rect"
alt="MEGIS" coords="0,0,82,67" border="0">
<area href="http://www.maine.gov/geolib" shape="rect"
alt="GeoLibrary" coords="83,0,132,67" border="0">
<area href="http://www.megug.org" shape="rect" alt="MEGUG"
coords="133,0,206,67" border="0">
<area href="http://www.nsgic.org" shape="rect" alt="NSGIC"
coords="207,0,298,67" border="0">
</map>
<br>
<br>
<font size="-2"><span style="FONT-FAMILY: Arial">State House
Station 174</span><br>
<span style="FONT-FAMILY: Arial">264 Civic Center Drive</span><br>
<span style="FONT-FAMILY: Arial">Augusta, ME 04333-0174</span><br>
<span style="FONT-FAMILY: Arial">(207) 215-5530</span><br>
<br>
<span style="FONT-FAMILY: Arial">69</span> <sup
style="FONT-FAMILY: Arial">o</sup> <span
style="FONT-FAMILY: Arial">47' 49.5"W 44</span> <sup
style="FONT-FAMILY: Arial">o</sup> <span
style="FONT-FAMILY: Arial">20' 54.5"N</span> </font><br>
<br>
</div>
<div> </div>
<br>
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