[Xastir-dev] Plotting a GPS point on a map

[Michael Pawlowsky]

Hello,

I'm working on a OSI ground station software package
for amateur UAVs and one of the views is a map view
that plots the planes position on it.
I figured you guys are experts in this area, so I was
hoping I could ask you a few questions.

For the GPS coordinates I'm converting everything in
to seconds up to a precision of 1/100th of a second as
a whole number.
I believe this is what you are also doing.

Naturally I have the NW and SE coordinates of the map.
All information is using WGS84.

Plotting longitude is no problem, but of course
latitude is. 
So I was hoping you would share with me your formula
to do this.
I've seen several on the net, but I'm sure you guys
have this already well worked out.

The second function I'm looking for is to get the
distance (in Km preferred but anythign will do) to
calculate the distance between 2 points.

Thank you for any assistance you can provide.


Regards,
Michael Pawlowsky
R/C Pilot Group