I want calibrate (georeference) a bitmap that represent a mappoint map.

Is there an algorithm, possibily in c#, for map calibration?
I found a geo-referncing algorithm in codeproject.com ( http://www.codeproject.com/useritems...sp#xx1360144xx ) but this algorithm take only 3 reference point.

What kind of projection mappoint use?

Hi,

Is the article you mention not what you wants ? I think it is good for relative small area's.
As far as I know mappoint assumes that earth is a perfect sphere.

The small area is good for my work.
Now I read that mappoint use NAD83 that is ,for small area, equivalent to WGS84 (used by map calibration found in http://www.codeproject.com/useritems...sp#xx1360144xx )

The only problem is that this algoritm take only 3 point to calibrate raster.
Three point are few?

Hi,

I dont understeand the problem you have. What is wrong with 3 points ?

Are 3 points few for calibration?

Hi,

3 points are few enough, you need them for a 2D calculation. But I tought to understeand you had a problem with 3 point ?

Using only three measurements, you have no way of telling whether you made any mistakes, and furthermore using more measurements makes it much more accurate.

What I need is to use the "least-squares adjustment" (suggested by a thread in a forum) when you have more measurements than initially required.
This method is very often used for determining affine transformation parameters, I want to find an algorithm that explain how to do it.

Hi,

Thank you, I get your point now. I dont know it myself, but maybe someone else know. A quick googling gives alread a lots of info, but as always it is a mess to find the interesting ones. Good luck