I'm speaking out of my arse right now, so take tha tin mind while reading....
I believe the follwing to be accurate...
The zip code is used to determine the closest 'weatherstation' and then there is a weatherstation code used to get the weather/forecast data from the weather server that corresponds to the local weather for that particular zipcode.
In theory,
If the GPS mapping prgram contained the zipcode information, you could read that, lookup the local weatherstation code and dload the text file corresponding to the location you are in.
The weather data is an ascii file with codes that correspond to the various variables for the weather, i.e. rainy/windy 75/80 cloudy/partly cloudy... plus the 5 day forecast. I belive this can all be found by Googling weather related sites like
www.nws.noaa.gov.
This site breaks down the codes somewhat:
http://www.nws.noaa.gov/mdl/NDFD_GRI...der/ndfdwx.php
This would be how MEEDIO and Centrafuse get their weather data, I believe.
The key would be updating the INI file with the weathercode as you move, which I belive requires a restart of the application (not good). But I'm sure a programmer could figure out how to make the information dynamic vs. static.
once, I speak from a vast empty space of knowledge and cannot be held liable for any rain that falls on your head while it says it should be sunny.
Hope it helps...