Using GPS/Laptop to determine % grade in mountains

[+bdaniel]

I travel a lot with a fifth wheel camper and truck. I've had a lot of fun with my Garmin MAP76s hooked to my laptop for real time tracking in ExpertGPS and Mapsource.

 

I would like to write a Visual Basic program to read the NEMA data from the GPS and use time, MPH and altitude to determine the percentage of grade on roads in the mountains. Example 6% grade, 8% grade etc.

 

Visual Basic has a comm object and I can see the NEMA data coming in on the serial port. I was just wondering if anyone else has done this or has any ideas for the computations.

 

Thanks,

Bobby