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TopoPhoto maps offer vivid detail

Sun., April 20, 2008

Take the twisting lines of contour and iconography of a United States Geological Survey (USGS) topographical map, blend in a high-resolution aerial photograph, and you’ll get a TopoPhoto, a new type of map from

This hybrid feat of cartography, announced by last year, is possible now because of new government-issue color aerial photographs taken between 2003 and 2006.

Instead of traditional color-coded vegetation boundaries and blue swaths of ink for water, a TopoPhoto map presents area geography as it’s seen from above. Forests are discernible as bushy bunches of trees. Rivers are winding dark lines.

On top of this picture overlays lines of contour, elevation markings, place names, municipal boundaries, and, if desired, latitude/longitude or UTM tic marks and grids for navigation.

The resulting map, I found, was difficult to comprehend at first glance, as the details from the underlying aerial photograph trumped the map markings for attention. I’m so used to reading and navigating from the traditional USGS look that the TopoPhoto form threw me off.

On a regular topo map, areas of minor detail — say a large meadow — are connoted via a single shade of ink. But on a PhotoTopo map these same low-detail regions might be a mess of colors, with crisscrossing lines, amorphous blobs, and other shapes showing varying vegetation types.

But this kind of attention to detail — though potentially overwhelming at first — is the whole point of a PhotoTopo map.

Hunters, as one example, might better scout ground cover, vegetation density or new water sources seen on the aerial photograph.

Also, because these maps use recently-taken color photographs, new details show up that are absent from a USGS map of the same area. sells PhotoTopo maps for most of the United States. (See a diagram showing available regions at

As with all products, the maps are customizable on the web site, where users pick a location, the map’s size and scale, paper type, and other details. It’s a fun and easy process.


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