I don’t know how I can be expected to figure the distance from Viking 2 to MSL when I can’t even measure the distance from one step to the next.
When I started using the pedometer I measured my stride length and have been using that for distance calculation. Yesterday was the first time I compared pedometer distance to a map distance, and the two disagreed by about 10%. Either my measured stride length was too short or the pedometer was missing 10% of my steps.
Today I took another walk of known length. Along the way I did some step counting of my own which agreed closely with the pedometer — at one point I counted 500 paces and the pedometer read 502. Afterwards I tried directly measuring the distance of 30 paces in my driveway. Both of these and yesterday’s walk give stride lengths agreeing within an inch and disagreeing with what I’d been using by about three inches.
(Of course I’m sure stride length varies depending on circumstances. I have no idea how to estimate and correct for that, though, so I won’t try. Also the pedometer probably gets false positives when driving, etc., which I haven’t looked into.)
So I’m retroactively revising my distance estimates. As of last night, instead of 153.9 km as calculated with the old stride length, I now am claiming 171.9 km.
MarsWalk kmz file (for Google Earth — View >> Explore >> Mars)