The Map Room recently covered the National Agricultural Imagery Program (NAIP). Now don’t be confused by the Agriculture part of the name, because the NAIP is of value to a much broader audience. NAIP offers very recent, natural-color aerial imagery of almost the entire U.S., at a relatively high resolution. Full county mosaics are $50. For my county, there is a 2006 image with a resolution of 2 meters/pixel, and a 2005 image at 1 meter/pixel. The image at left, of the Big River estuary and Mendocino, CA, is supposed to be 2 meter resolution. The resolution doesn’t look quite that sharp to me, but nevertheless, I can make out recent changes in logging roads in the area I frequent for mountain bike rides. The image to the right below, shows a 3-D view with waypoints, that I created using OziExplorer.

The color county mosaics are in MrSID format. You can use OziExplorer to work with these files, and the NAIP website lists several viewers. Quarter quadrangles are available in GeoTIFF format. Here’s the latest (2005) aerial photo coverage map for color county mosaics.

Unfortunately, we’re dealing with the feds here, so ordering is a pain and delivery is slow.

There is a wealth of Geographic Information System (GIS) data available on the web — everything from public land boundaries to international contour files. It is amazing what you can find. A few examples:

• I live in an area dominated by private timber lands. I found private timber company boundary files offered through this website.
• Looking around for public land boundary files, I discovered that the California Department of Fish and Game owns a series of ecological reserves. Not only did I learn about this little known treasure, I found boundary files as well.
• I was fortunate to be able to visit Ecuador a year ago. I used files from the GIS Data Depot to create a contour map of the country, that I was able to load onto my GPS receiver. I was able to find other sources showing roads, streams, cities, provincial boundaries and major volcanoes

GIS files are most commonly found in either .shp (shapefiles) or .e00 formats. Unfortunately, few consumer-level GPS mapping programs allow you to utilize GIS files.  OziExplorer is my favorite program for working with GIS files. Using it, you can convert these files to tracks and points, and even display this info on your GPS. Another program, ArcExplorer, is a free GIS viewer, but it lacks GPS compatibility. The image, to the right above, was captured from OziExplorer. It shows public land boundaries in green and private timberlands in yellow, superimposed on a color aerial photo.

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