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    Michael,<br>
    <br>
    &nbsp; 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"
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      <div><span class="009512717-13122011"><font face="Arial" size="2">I
            am trying to convert the&nbsp;historic USGS topo maps
            (GeoPDFs)&nbsp;into GeoTIFFs<span class="543185718-13122011"><font
                color="#0000ff"><font color="#000000">&nbsp; with GDAL 1.8</font>&nbsp;</font></span>.&nbsp;
            A very straightforward thing to do is</font></span></div>
      <div><span class="009512717-13122011"></span>&nbsp;</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>&nbsp;</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.&nbsp; 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.&nbsp; 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>&nbsp;</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>&nbsp;</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?&nbsp; I don't see anything like that in the docs or
              the list archives.</font></span></div>
        <div><span class="009512717-13122011"></span>&nbsp;</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.&nbsp; What fun!</font></div>
        <div>&nbsp;</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>&nbsp;</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&nbsp;&nbsp; 44</span> <sup
              style="FONT-FAMILY: Arial">o</sup> <span
              style="FONT-FAMILY: Arial">20' 54.5"N</span> </font><br>
          <br>
        </div>
        <div>&nbsp;</div>
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        <pre wrap="">_______________________________________________
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