you can project usgs topo and aerial images onto 3d contours using 3dem, from Visualization Software. first, you have to download the terrain data in a dem (digital elevation model) sdts (spacial data transfer standard), or srtm (shuttle radar topography mission) file manually, for the area you want to render.
  portland, sdts contour w/ usgs images. |
once you get the contour loaded into 3dem, then you need to choose an overlay to project on the topography. this can actually be any image, from landsat7 satellite images, usgs topo maps, or whatever. i wanted to see the aerial and topo maps... and depending on the image, you may have to calibrate placement with lat/lon points - which is a hassle.
here you can see the overlay area lining up over the contour.
what worked well for me - was to export aerial and usgs topo export images using the bigjpeg utility in usaphotomaps - then import those images in 3dem. i'm not sure if 3dem used the image name, meta data, assoicate file, or image content -- but 3dem appears to line up placement automatically. brilliant.
here are some results using the portland area, from downtown to the southwest hills.
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even top down views look better with artificial shading (even if only slightly) ...
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next - it might be interesting to see blended images (topo and aerial overlays) together. you can also project gps tracklogs, or save files in various format like vmrl.
links:
http://www.visualizationsoftware.com/3dem.html
gallery:
http://www.visualizationsoftware.com/3dem/gallery.html
terrain data:
http://data.geocomm.com/