I did a survey of the various navigation apps out there and decided to give Path Tracker a try.  It was only 99c.

Path Tracker is not like TrackThing where you get a graph and stats on the iphone. Instead, data is uploaded to a website as with GPS Tracker.  Except I never could get GSP Tracker to work well enough for me. As with any iphone GPS app, make sure you give it 30 sec to lock in before you ride.  Also, make sure you place the phone away from any metal. Starting the app is easy enough, click on ‘Start New Path’.

After you have registered, you can go to the site and see a Google map of your ride.

You can also zoom in and get details on each point

As useful as clicking on these points are .. (although more useful would be the ability to download a spreadsheet of this information .. need to explore that) .. it seems to me that some rounding has been performed.

More interesting to me however, is downloading the raw data.  You can do this in a variety of formats; I prefer GPX track file format.  This give me Lat, Long, Elev, and Time. From these points you can do your own calculations for velocity. (veloc=distan/time).

… however …

This is the iphone we are talking about here.  The error on the GPS is pretty wide. 20′ at times, and that is when its getting max satellites. So what I want to do is write my own smoothing algorithms as well as deal with erroneous datapoints that can occure when accuracy drops. And that is what I like about Path Tracker. I can take the GPX data, run some calcs and spit out a graph or raw data for excel. Below is a graph from a short ride on the ebike to get groceries.  Here I have mph and elevation.

Future work?  Improve the calculations (seems to be 4-5mph low), write a smoothing algorithm, functions to deal with 0 data points, rate of climb, rate of acceleration, etc..

Share and Enjoy !