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DefineFromControlPoints: how do I enter all those points?

Question asked by thomasa on May 12, 2016

I need to recreate the functionality of the link table in the georeferencing toolbar. I have sets of ground control points (usually between 5 to 30 gcps for an image) and need the resulting RMS errors for a given transformation - there is no need to actually rectify the images.

I have trouble understanding the DefineFromControlPoints Method.

The documentation says. 'Defines the best affine transformation between two sets of points'

but the arguments are defined as        ByRef fromPoints As IPoint

which I understand is one point, not a set of points.

This sample (rather old, but one of the few available I found)

http://edndoc.esri.com/arcobjects/9.1/ComponentHelp/esriGeometry/DefineFromControlPoints_Example.htm

states

 pAffineTrans2D.DefineFromControlPoints 4, pPtFrom(0), pPtTo(0) 

which appear to be single points from a point array, so again actually only one ground control point.

I am confused...

So again my question: can anybody show me how to use a set of points with DefineFromControlPoints ?

Any help is appreciated!

 

Cheers

Axel

 

 

ByRef fromPoints As IPoint

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