Help with .FLT file gps_engine flight path point decoding

Question

Hi,

I am trying to understand the encoding of the flight path points fpn to fp0 under the gps_engine section of a .FLT file, as defined here:

http://msdn.microsoft.com/en-us/library/cc707071.aspx#[gps_engine]

I can get the equation for longitude to work, but I cannot for the life of me get the one for latitude to work. Is the equation in fact correct?

"The latitude is coded as: 128 * ((latitude as a decimal value) * (90.0 / 10001750))"

It seems to me that this equation would always yield such a small value that the hex value would always be zero.

Also, how are negative values handled? (W longitude and S latitudes?)

Could somebody please explain this? I'd ideally like to see an example showing how to utilize the equations to translate the hex values of the flight path points to real latitude/longitude values.

Thanks very much for any advice!

- Bob

Answer 1

nerd.....