Mapping Hacks

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Chapter 2, Mapping Your Neighborhood

#18 Why You Can’t Watch Broadcast TV

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If your map has large blocks of blue where you were expect-

ing to see land, then you may need to obtain and convert

more DEMs to cover the missing ground, as described

above. If you’ve converted the additional files, but you’re

still seeing errant ocean, double-check the filenames of the

converted .sdf files to make sure that the latitude and longi-

tude values in the filename are correct.

Adding Context to the Coverage Map

Now, although the coverage map we made for KQED-TV is interesting, and

quite cool in its own right, it’s lacking personal context. We can see where

the reception coverage extends to, but it’s hard to tell where exactly that is

Figure 2-13. A SPLAT! broadcast coverage map for KQED-TV

Why You Can’t Watch Broadcast TV #18

Chapter 2, Mapping Your Neighborhood

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on your mental map. Fortunately, SPLAT! offers a way of adding city loca-

tions and political borders to help orient you and readers of your coverage

map.

You can get city location data from the U.S. Census Bureau at http://www.

census.gov/geo/www/cob/. Download the Incorporated Places data for Cali-

fornia in Arc/info Ungenerate format from this site, unzip it, and feed it to

the citydecoder utility that ships with SPLAT! Use the sort command ...