I carry a GPS with me on long bike rides and pull the resulting trace into Google Earth and Garmin's MapSource software. Google Earth is nice for looking at, but doesn't provide much useful information, and MapSource is pretty awful to look at (and will only run in Windows so I have to boot up VMware) but does provide elevation maps (as well as the ability to load maps). I recently started using a bike computer with cadence, and a heart rate monitor, and the last missing piece of information was total elevation gain over a ride. This information is nowhere in MapSource or Google Earth.

I can get GPX format (The standard interchangable format for GPS information) files out of MapSource and it's just XML, so after trying several tools online and several programs I downloaded that didn't work, I wrote a quick python script to get me the info I want. Hopefully this will help someone else:

from xml.dom import minidom

file = minidom.parse('./file.gpx')

min = 1000000
max = 0
gain = 0
loss = 0
last = 0

for node in file.getElementsByTagName("ele"):
        cur = float(node.childNodes[0].data)
        if (cur > max):
                max = cur
        if (cur < min):
                min = cur
        if (last != 0):
                if (cur > last):
                        gain = gain + (cur - last)
                elif (cur < last):
                        loss = loss + (last - cur)
        last = cur

print "max: %.2fft" % (float(max * 3.2808399))
print "min: %.2fft" %  (float(min * 3.2808399))
print "gain: %.2fft" % (float(gain * 3.2808399))
print "loss: %.2fft" % (float(loss * 3.2808399))

So for my 43 mile ride on sunday:
max: 1110.63ft
min: 773.16ft
gain: 3328.98ft
loss: 3232.78ft

Getting those numbers were a lot harder than it should have been! Good ride though..