Re: [NTLK] GPS Map

Well, there are more than 2 kinds of map projections than
"rectilinear" and conic.
Anyway. Obviously the RectMap2.exe uses a map projection algorithm.
I do not know the projection it uses but you can easily find a map
projection that suits you and use the corresponding algorithm. Which
one you will use depends on the scale of the map image and also the
region of the earth it depicts.
Usually, maps have the projection info written on them. Or you can
find this info on the website of the map provider.
Nevertheless, the accuracy will be good enough for most uses.
Hope it helps.

Kostas

On 7 Jul 2008, at 01:55, Matt Howe wrote:

> Once you have a map image you have to pick three points on it if it is
> rectilinear or nine points if it is conic. These points consist of 4
> pieces
> of data, Lat, Lon, X pixel and Y pixel. These numbers are then
> entered into
> a utility. I use rectilinear maps so I use three points and
> RectMap2.exe.
> The Lat and Lon points must be in degrees and decimal minutes. The
> utility
> then produces a set of offset adjustments that must be placed into
> the NTK
> project to compile into the map. RectMap2.exe uses a question and
> answer
> text only format, one slip and you can enter all of those numbers
> again. I
> want to make a VB project where you can enter any style coordinates
> for the
> three points and when done click a button and get the export needed.
> In
> order to do this, I need the algorithm used by RectMap2.exe create the
> offsets.

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Received on Sun Jul 6 21:08:08 2008