An Example of Trail Map Accuracy

This is not meant as a critical post. I know that people who put trail maps together do the best they can with their maps.

For the record, I loved the hike at Bell Cow Lake!

I used the online trail map, and Google Earth, to overlay our GPS track with the trail map. The technique is called georeferencing, and Google Earth does a great job. Here is what I ended up with:

Bell Cow Lake Red Trail Georeferenced

There are a couple things to note. The actual trail clearly does not match the trail marks. The trail goes outside the boundaries of the park a couple times (look at where the trail crosses the road on the lower right).

If you look at the north section of the trail, there is a blue pushpin. The Redbud Trail is marked by red and white plastic strips tied to trees, but it intersects in a number of places with blue and white strips. I looked briefly at Google Earth , and those look like bypasses to shorten the Redbud Trail.

I’m going to offer to send my GPS track to the City of Chandler, or maybe just generate a new trail map and send it to them. Now, that would mean I would need to go back and hike the Flat Rock Trail, and the rest of the Redbud and the “blue” sections… 🙂

04 April 2015 Update

So today I got back to Bell Cow!  A group of Boy and Girl Scouts hiked the Flat Rock trail, and I captured the GPS track.  Here is the map above, overlayed with the GPS track in orange.

Bell Cow Lake north and south overlays

Not surprisingly, the track captured by the GPS does not match the trail map.  One really different parameter is the trail mileage.  The track looks like it goes out to Point G, and that point is just over 5 miles from the trailhead, not 6.2 miles.  Just above Point G, where the trail goes pretty much east to west, there is another loop that starts and looks like it heads off to the NW.  I would guess that trail is closer to the 6.2 miles mark.

As with the north side, there are a couple trail deviations that are not accounted for in the mileage.

Regardless of GPS differences, this a a great place to hike.


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