As a runner training for a marathon for the first time, I found myself wishing I had an easy way to know the exact distance a certain course is, without having to drag a GPS or pedometer around on my runs. Looking at Google Maps, and knowing there was a vibrant community of geeks hacking it, I knew there had to be a way. So here it is.
It works fairly well. I charted three of my favorite runs, and I was within about a tenth of a mile of how far I thought each run was based on what this site said. You can set it to english or metric units, and it will mark your mileage or kilometers as you go along. You can create a permalink to the page, and it has a shortcut to create a TinyUrl to make cutting and pasting into an email or bookmark easier.
I found the best way that works for me is to zoom in as much as possible on the start location, and to create the route I ran a short distance at a time. You create new points by double clicking on the map, which also centers the map to that location, so it is very easy to maintain the entire route without zooming out. I also put the map into satellite or hyrbid mode so that I can go off of the actual part of the road or trail that I run on. Once I have finished, I zoom the map out enough that the entire route will appear, and create my permalinks and TinyUrls from there.
The only bug I have noticed so far was that now and again the mile marker appears in the wrong place. And by the wrong place, I do not mean at the wrong mileage point along your course. I mean that it can appear completely off of the course you ran and nowhere near there. That only happened a few times in the dozen or so maps that I have created, and I can not find a way to purposely make it happen.
I am very much looking forward to implementing something similar here once the framework for the training diary is in place.