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I have a scan of an old map, that I want to geo-rectify so that it sits neatly under a vector dataset of property boundaries.

I am following the example at this link “Adding GCPs to a scanned topographic map”

RasterGCPSetter (safe.com)

I have picked three GCPs

I have a JPEG Reader for the scanned map

I use a RasterGCPSetter to set the three GCPs

I then use the RasterGCPApplier to apply the GCPs (I downloaded GCPApplier from the hub)

At this point it all looks great. The Inspector shows that the scanned map has rotated about 10-15 degrees. I am only using three GCPs, so this is an expected result.

I then use a GeoTIFF Writer

But the GeoTIFF output has no rotation :-(

What am I doing wrong? How do I write out a raster that is rectified?

I have not tried this, but you probably have to resample it using the RasterResampler.

Thanks! I used the RasterResampler and chose Resolution Specification: Cell Spacing

A value of 1 (for 1 metre) worked quite well as an initial attempt

I successfully saved the result as a GeoTIFF and then opened that GeoTIFF in MapInfo

Cheers!

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