Wednesday, August 13, 2008

How to Create an Elevation Profile

RM1200 Profile and Maps

Not sure if it was a question or not but a post on the phred mailing list queried creating an elevation profile. The easiest way that I know of is to enter the route in to Bikely and then take the profile from Bikely. You can enter a route into Bikely very quickly (see my Bikely hints here). The profile for the Rocky Mountain 1200 shown below comes from Bikely.

It took me about a half hour to enter the Rocky Mountain 1200 route into Bikely (and about three hours to research and write this post). Once the route was complete, I displayed the elevation profiles. I copied the elevation profiles using the prtsc key and pasted them into the Windows Paint program. One of the profiles, after trimming, saving and importing into Blogger appears below.

The html text for the Bikely map was copied from the Bikely share menu into this post. The Google Map was added by saving the Bikely route as a KML file. Then I opened the KML file using Google Earth and shared the route as a post to the Google Earth community. I was able to copy the html code for the Google Map below from the post to the Google Earth Community. The Google Map has a good shaded relief view as well as the ability to search for business, parks and other places of interest along the route. I used a similar process for the profile and maps for my SIR-300 ride report.

What type of profile you need depends on what you want to do with the profile or the profile data. An example: for the Big Lebowski 600k, I used the elevation data from my Garmin GPS recorded during a motor tour of the route. Then I copied the GPS route data as text from my Garmin software and pasted it into an Excel spreadsheet. Then I setup Excel to calculate segment lengths and grades (percent slope) and the result was used to plot the profile data as xy line graphs. I was able to describe each incline very accurately using the spreadsheet calculations.

I found that a single profile once plotted out for a 600k was too large to be very useful in a document or a route sheet. Once re-sized to fit into a document, the 600k profile became too tiny to distinguish detail. A rider needs a profile they can follow as they ride the route. So I created three profiles split into 200k distances. That amount of data seems to result in a minimally useful profile for road use. It was fun playing with the numbers and setting up the spreadsheet for repeat use, but the riders didn't know the difference and I could have done the same with a tiny fraction of the time investment using my experience and judgement to estimate and say "There is a 10 mile climb at mile 260 that has a 5-percent average slope."

Just a quick note about the maps and profiles. They are a good resource but they would be even better with pictures taken along the route, and waypoints established for water stops, controls, and other important information. My maps generally don't get to that level of quality, and maybe they should. But I do use the maps and profiles on the back side of the route sheets. When printed in card format, the rider can esily turn the card over to check the profile and map, or not. Paul Whitney uses Bikely to show the ORR-600k fall brevet here.

Update Aug 19, 2008: The Bikely profile has a total elevation gain problem. The total elevation gain shown on the Official RM1200 Profile Sections shows a total of 8,240 meters or 27,034 feet of elevation gain.

Bikely Route Profile and Map
Bikely Elevation Profile for RM1200

Google Map via Google Earth

View Larger Map