Thursday, February 18, 2010

Birkie Elevation Profile

[Updated 2/19 with high quality profile linked, 2/22: more hilly fun here.]

So, at times in the past, I've spent a bit of time looking in to the elevation profile of the Birkie Trail. The Birkie folks have one, but, well, it kind of stinks. So, I decided to do them one better. Google maps got good aerial photos posted on their site this past year, so it is easy to trace the trail from Cable to Hayward. I used gmap-pedometer to do so (it's having trouble loading the whole thing) and then used Gmap to GPX to convert it in to GPS data. That was exportable in to excel, and from there it was a hop, skip and a jump (and some google searching to figure out how to convert latitude and longitude in to distance) to having an excel file with 2300 points each with a distance and an elevation.

Thus, I was able to create a detailed chart of the Birkie trail elevation, kilometer by kilometer, for the whole race course. And, of course, post it here. Click it to enlarge, although the quality is less-than-stellar (thanks, blogger) but for a far better version click this clicky. That's on my personal website which is crash-prone but should work for now. But it is pretty damn sweet.

It's annotated with some major landmarks. And I'm not going to say it's perfect, but I think it shows all the major climbs. The .xls file is up to 2.3 mb, and has things like slope and such, which are poorly defined measurements (the more points you sample, the better they get, but you can never get a perfect measurement, see coastline paradox). In any case, this is enough for now.

A few stats: the race starts at 408m and drops to 366m. However, it has a total climb of more than one kilometer—1041 meters of climb. And in the 10k from McNaught Road to High Point, the trail ascends 400 feet. No wonder its a good, fun (hard) time. High point is 534m (1752 feet; the sign says 1730), and Lake Hayward, the low point, is 359m (1178 feet) amsl.

If you want to geek out a bit more … to calculate distance from changes in latitude and longitude, I get excel cells which look like
=(3958*3.1415926*SQRT((E1938)*(E1938) + COS(A1938/57.29578)*COS(A1937/57.29578)*(F1938)*(F1938))/180)
so that's fun. But it works; the distance comes in at 49.45 km which is within 1% of the advertised distance and not worth trying to adjust to 50k (i.e. multiplying distances by 1.01). Also, the Birkie has about 100 feet of climb per mile, or about a third the climb of the Hut Traverse in the White Mountains. Which probably means very little in these parts, but it's hiking 50 miles with ~15,000 feet of climb. In a day.


  1. You didn't ask, but, here's the URL for the good file:

    That's on my personal site which may crash at any time, though ;)

  2. I've done something similar with a Garmin GPS unit and National Geographic TOPO map program. The training specific models like the Garmin 305 are ideal for this. The process actually is very simple. First you ski the Birkie. Then you download your data from the GPS into the TOPO program and it shows up on your map. Then right click on the track that is the route you just skied and choose the Build Profile option. You end up with a profile of the course you just skied that is overlaid on a USGS topo map. I think the tricky part is to make sure you hit the start button at the start of the race and hit the stop button at the end. I hope to have a new map generated this year. The one I had from last year when I did the classic race got lost whem my laptop hard drive crashed.

  3. Nice. I am doing the fat bike birkie and was looking for info on the course. great effort.

  4. You say total climb is 1041 meters. But Birkie site says climb is 1398 meters. Just curious which is correct?

    - Chris