[Proj] Rectification of maps

Thomas Flemming tf at ttqv.com
Fri Sep 23 12:50:03 EDT 2005


> It seems like what you would want is a rubber sheeting transform
> of some kind based on a bunch of reference points.  Two reference
> points wouldn't give you much information.  PROJ.4 does not
> address this issue.  I do have such a capability in GDAL -
> underlying transformations based on reference points and a way
> of applying it to resample rasters.
Puh, this sounds good, btu I think GDAL is too big for me to understand for 
this single task.

> I would recommend an eight-parameter projective transformation based on
> four points of a graticule.  The panelling of such is identical to the old
> graphical technique employed by cartographers of 20 years ago.
I have this eight-parameter projective transformation already in my software, 
but it does not work good for maps which are stitched from many scanned papermaps.
In this case I need much more control points.

Best regards,

**   Dipl.-Ing. Thomas Flemming
**   Software Development
**   Touratech AG
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