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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.

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rgds, Wilfried Mestdagh
www.mestdagh.biz
MapPoint coding demo
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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 ?

__________________
rgds, Wilfried Mestdagh
www.mestdagh.biz
MapPoint coding demo
Order MapPoint 2009 with Routing and User Tools Spreadsheet

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 ?

__________________
rgds, Wilfried Mestdagh
www.mestdagh.biz
MapPoint coding demo
Order MapPoint 2009 with Routing and User Tools Spreadsheet

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

__________________
rgds, Wilfried Mestdagh
www.mestdagh.biz
MapPoint coding demo
Order MapPoint 2009 with Routing and User Tools Spreadsheet