Recently I had the opportunity to create a course map and elevation profile for the Canylonlands Half Marathon. This is one of my favorite races, and I’ve participated in either the half marathon or the 5-mile event for five of the last seven years. My familiarity with the courses would definitely be helpful in creating accurate maps, but I also felt particularly obligated to present the striking beauty of the course through cartography.

Fortunately, the state of Utah has the best GIS data clearinghouse I’ve ever used: the Utah Automated Geographic Reference Center (AGRC) and associated GIS Data Portal. From this website, users are able to download many datasets, include 2007 1-ft color aerial imagery and 5-meter digital elevation models…for most of the entire state…for free. Finding data at that resolution, currentness, and cost is truly amazing, and for that reason I love the AGRC and love making maps for locations in Utah.

The 1-ft color imagery allowed me to zoom into the route very tightly (about 1:1000), and precisely digitize every tangent of the route and closely simulate its certification. This helps makes the elevation profile and the mile markers more accurate.

But the 5m elevation model was the real gem. For most of the United States, the best you can get is 10m resolution. In some places you can get no better than 30m. So to get 5m resolution for a tiny town in the middle of Utah is remarkable. I should note that 2m DEM’s are publicly available for some locations in Utah.

What a 5m DEM provides is better hillshading, which is the backbone of this particular map. Every ridge, canyon, drainage, and other topography are sharply defined, even at large scales. This not only makes the map more vivid, but allows it to be blown up to larger scales (and larger prints), and still look wicked good. In addition, the extra resolution of the 5m DEM accommodates better profiling, especially in narrow canyon areas. For much of the Canyonlands race, runners are tucked right up against a huge sandstone cliff. This can really mess with an elevation model, which tends to interpolate/average elevation values in steep areas. With a higher-resolution DEM, this effect is lessened.

The final maps turned out well, in part to the quality of the underlying data. I ended up making an overall map, an elevation profile, and zoom-in views of the start line and finish line. The race management also printed a poster version of the map, which is available for purchase here.

Canyonland Half Marathon poster

Map showing zoom-in view of finish line