The evolving purposes of this dataset
This dataset was initiated ten years ago, to describe general route locations and identify areas by which races would be permitted by rather than specific linear routes. While those programmatic EA efforts might again be revived, the dataset has found multiple purposes throughout the years. For the BLM, GIS routes allow for the overlay of administrative (i.e. legal land descriptions, surface ownership) and resource (wildlife habitats, hydrology) data layers. When new routes were to be compromised of already permitted segments, the dataset became invaluable. Maps were printed, marked with ink and then re-digitized back into GIS.
Google mapping tools provides solutions that integrate both recreational and professional level GIS and GPS systems. For those outside the BLM GIS system, KMZ files enable proponents to view, build and submit proposed routes electronically. This will allow for the efficient 2-way communication of spatial data and smooth the permitting process.
30 years is a long, long time ago
In technology terms, three decades is big. For half of this time, only the military had GPS. BLM files for races are far back as the 1980s were canvassed. Maps were pulled from the files, taped to a digitizing table and traced. Some were badly xeroxed copies and/or fragments of sketched maps. USGS maps the data are accurate to 166 feet (1:100,000) or 40 feet( 1:24,000). Command-line GIS edit were made on an orange CRT monitor which did not display graphics. Most of the pre-2005 routes were digitized. As technology made it more feasible, some of the later routes are derived from GPS or kml files. The resulting dataset has been published as individual routes by club and year.
So, how can I tell what’s what in this network of routes?
The many overlapping lines are a result the same routes for multiple races. Each route is kept as a distinct lines so when you click on one line, you get the information for that one route. The routes are clearly identified by club and year. The visibility of each individual routes can be turned on or off to help you isolate and display routes of interest.
Why is the data so far from the travel routes in the satellite imagery?
The original paper maps were rough and the data was digitized with the intention of showing general locations. The route data will have to be read with this understanding and some common sense. For example, dead straight stretches or where routes cross terrain that would the best riders couldn’t tackle means the gentle curves of the route were digitized as a direct line from Point A to B. The data’s origins make it evident why its accuracy doesn’t even approach that of today’s sub-meter imagery. The data was never implied or intended to stand up to the accuracy.
Why do the driving tours and elevation profiles act erratically?
Since these are individual routes, there is the expectation that they can be viewed with Google Earth’s driving tours and elevation profiles. Sometimes this works but more often, it does not. This is an artifact of how the data was created. Routes often covered more than one paper map. The digitizing process is map by map and the flow of the route got lost. Many of the routes were created in GIS from portions of previous route so while the route appear linear to the eye, the cut-and-paste fragments jumbled the order of the route. Of course, you can always manually pan along a route. While tours and elevation profiles are cool, this dataset was created long before Google Earth was a twinkle anyone’s eye.
Are there plans to clean up and ‘fix’ the data?
Going forward, the data will improve as route proposals and post-race monitoring are submitted by electronically by GPS or KML files. For now, it serves the primary purposes to show route locations. There are plans edit this historical dataset but not immediately.
The Race Permit process
There are ongoing discussions how proposed races route proposals should be submitted in Special Recreation Permit process. Monitoring efforts before, during and after race events might help address the inclusion of more accurate GPS data in the future. For more on this topic be sure to check out the recommendation in the 2009 Motorcycle Race Route Report.