|Rather than displaying the elevation difference between the starting and ending location of a drive, it would be beneficial to determine the cumulative gain and loss throughout the drive. This would require tracking the elevation at each data point and having a summary field to determine Elevation Gain and a separate summary field to determine Elevation Loss.
This could be summarized in each drive record, plus the daily summary and possibly other places. This would be helpful to display in the leader boards, too.
|If you plan to use the Google Maps Elevation API, it appears that you're limited to 2,500 calls per day without having to pay. It may be smart to create a separate table for Long/Lat data and the associated elevation for that location, then create a separate service to ping the Google API to fill in any missing data within the limits. Perhaps this new TeslaFi elevation service can work every day to fill in all GPS locations captured thus far until you feel comfortable with the number of new GPS locations being less than the 2,500 limit per day, then you can start displaying the data on the site. Then the service, which is running every day, can fill in all incoming GPS locations that don't already have an elevation associated to it until it reaches the 2,500 limit for the day, then it starts over the next day.
Some other possible tools:
* http://viewer.nationalmap.gov/tnmaccess/api/services? (there appears to be an Elevation API to hook into)
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