= Summary =

1. USGS offers new topo maps as a geospatial PDF [http://www.gdal.org/frmt_pdf.html] for download [http://nationalmap.gov/ustopo/index.html].  Direct download of specific file: [http://ims.er.usgs.gov/gda_services/download?item_id=5365522]
2. Some users may prefer to have the Topo map as a geotif rather than PDF

= Details =

1. GDAL must be built with Geospatial PDF support, see the above link for details.  Confirm with: 
{{{
$ gdalinfo --formats
Supported Formats:
...
  HF2 (rwv): HF2/HFZ heightfield raster
  PDF (rov): Geospatial PDF
  OZI (rov): OziExplorer Image File
...
}}}

2. Use gdalinfo to get NEATLINE:
{{{
$gdalinfo OR_Newport_North_20110824_TM_geo.pdf 
Driver: PDF/Geospatial PDF
Files: OR_Newport_North_20110824_TM_geo.pdf
...
Metadata:
  NEATLINE=POLYGON ((421614.539994676539209 4956417.675689895637333,421413.787766160559841 4941008.479600958526134,409984.382813899661414 4941157.382794972509146,410185.135042413836345 4956566.578883905895054,421614.539994676539209 4956417.675689895637333))
Corner Coordinates:
...
}}}

3. Make an OGR datasource of the NEATLINE to use as a cutline in gdalwarp.  This can be two files, a .vrt and .csv
wkt_cutline_file.vrt:
{{{
<OGRVRTDataSource>
             <OGRVRTLayer name="NEATLINE">
                <SrcDataSource >NEATLINE.csv</SrcDataSource>
                <GeometryType>wkbPolygon</GeometryType>
                <FID>Record_Id</FID>
                <GeometryField encoding="WKT" field="wkb_Polygon"/>
                <LayerSRS>EPSG:26910</LayerSRS>
            </OGRVRTLayer>
</OGRVRTDataSource> 
}}}

NEATLINE.csv:
{{{
"Record_Id","wkb_Polygon"
"1","POLYGON ((421614.539994676539209 4956417.675689895637333,421413.787766160559841 4941008.479600958526134,409984.382813899661414 4941157.382794972509146,410185.135042413836345 4956566.578883905895054,421614.539994676539209 4956417.675689895637333))"
}}}

4. Use gdal_translate or gdalwarp to convert to geotif and if using gdalwarp, -cutline to the NEATLINE.
{{{
gdalwarp -cutline wkt_cutline_file.vrt -cl NEATLINE -crop_to_cutline OR_Newport_North_20110824_TM_geo.pdf OR_Newport_North_20110824_TM_geo.tif
}}}


= Notes =
 * There is probably a more elegant way to grab the NEATLINE for use.
 * This could be combined with gdalinfo to determine which file to download.  
{{{
gdalinfo "WMS: 
}}}