I got some great advice on how to transform a geoPDF to a geoTIF at Historical U.S.G.S. Georeferencing, which used the available downloads from this site. I would like to take it a little further and not only convert, but remove the border of historical USGS maps in order to be able to tile them in QGIS. Being a basic GIS user, I get lost in the "coding" involved to implement these practices.

How can I convert and crop historical USGS maps so they can be tiled in QGIS?

I am attempting to do this again, it has been a while. I made it through the steps and I get a cropped quad that has back areas along the edges. I don't believe this happened when I did this in the past.

enter image description here

  • There is no question here. please re-phrase into a question. – Brad Nesom Oct 21 '13 at 14:41
  • The black borders are really no color, the tiles should be transparent there. You get those artefacts if you reproject a rectangle into another projection. You can try -dstalpha or -dstnodata in gdalwarp to make the borders white. Better ask another question about it if the problem remains. – AndreJ Feb 28 '14 at 12:34

Here are the steps how I managed to clip your Geopdf from the last question:

  • Read the imprinted border coordinates clockwise from the map and put them into a text file like this:
1;POLYGON((-74.25 41.75, -74.0 41.75, -74.0 41.5, -74.25 41.5, -74.25 41.75))
  • Load the text file as text delimited file, with ; as delimiter and NAD27 EPSG:4267 as CRS. The polygon should match with the map canvas, leaving out the border.

  • Save the polygon into the same CRS as the tif file. This is a poly projection, and you find it in the user defined CRS list. Add the shapefile to the canvas.

`+proj=poly +lat_0=41.5 +lon_0=-74.125 +x_0=0 +y_0=0 +ellps=clrk66 +nadgrids=@conus,@alaska,@ntv2_0.gsb,@ntv1_can.dat +units=m +no_defs`
  • Clip the tif on the polygon file with Raster -> Extraction -> Clipper

The command line should look something like

`gdalwarp -q -cutline D:/Karten/shp/Länder/USA/Newburg-border.shp -crop_to_cutline -of GTiff D:/Karten/gdal/gdalwarp/Newburg.tif D:/Karten/shp/Länder/USA/Newburg-clip`

This is what I got: enter image description here

  • I did what you said and it worked like a charm. I am attempting to do the same thing from the Schunemunk geo.PDF using the following code, but I get an error. – LandArch Oct 28 '13 at 13:09
  • : Nr;WKT 1;POLYGON((-74.25 41.5, -74.0 41.5, -74.0 41.5, -74.0 41.25, -74.25 41.25)) – LandArch Oct 28 '13 at 13:12
  • In your data, the second and third point are identical. For a polygon, the first and last should be identical. – AndreJ Oct 28 '13 at 13:18
  • I guess it helps if you close the polyline, thanks. – LandArch Oct 28 '13 at 15:12

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.