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I have a map in a PDF file with boundaries that I want to plot onto a satellite image.

I have made a screenshot, saved it as tiff and imported it as a R raster object. Using click I have outlined the boundaries which I can now plot onto the raster object.

enter image description here

head of polygon data.frame:

> head(df)
       x      y value idx
1: 408.5 1041.5   135   1
2: 361.5  988.5   255   2
3: 344.5  997.5   170   3
4: 310.5  960.5   237   4
5: 312.5  950.5   237   5
6: 257.5  816.5   254   6

My goal is to convert the data.frame with x and y coordinates to a spatial object (sf or sp) and plot it onto a satellite image.

The problem is the projection: How do I convert my relative positions to a projection that matches that of my satellite image?

The original projection is UTM Zone 37, projection Transverse Mercator, Spheroid Clarke 1880 (modified).

(no answers on the GIS stackexchange site)

Henk
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  • down voters are welcome to explain why they think the question is not well formulated, so I can improve it. – Henk Nov 16 '19 at 13:07
  • Some sample data might increase your chances on an good answer (not my downvote btw).. – Wimpel Nov 16 '19 at 13:21

1 Answers1

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This operation ("georeferencing") can be done easily in QGIS.

Henk
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