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I have an old scanned topographic map I have to georeference. Unfortunately there is no coordinate system stated and it has just on reference grid point on it. Besides that it states in the down left corner x and y in 1000 steps ranging from 1000 to 3000. It also states the scale 1:10000.

What would be the best way to georeference this kind of map? Would the scale be of any use? It is a mountainous area too, so the surface changed a lot in the meanwhile.

Edit: Here is a small part of the map for better illustration. It could be, that they set up their own local reference system, so would it be best to georeference using features on the map? enter image description here

  • 0 down vote Besides the known point, are there any other points which can be identified in another map? If it is an mountaineous region, there are maybe some peaks? – Mesa Mar 27 '18 at 15:10
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    The scale will only be useful if you can figure out the coordinates. If is a surveyor-created map, it might be State Plane feet or meters. A hiker's map might be UTM. I would look at topo maps of the area that have a known coordinate system(s), such as the ESRI online maps or a better USGS map. Also, geographic change is not usually that random; I have georeferenced old river maps despite many changes. There are probably a few peaks that are unchanged. – danak Mar 27 '18 at 16:08
  • I wonder what area it is that mountains are changed since map was drawn... Hard to say without seeing the map, but from my experience peaks and sometimes river curves can be helpful if there is no man made features on the map. Scale could be useful if you know size of the original map but still need one reference point. – Mat Mar 27 '18 at 18:19
  • It has peaks on it, but the primary land type on the map are glaciers, which have vanished quite a bit since the map was drawn (in the 1960s). Does anybody have a recommendation for basemaps of Africa.? – Aldi Kasse 2 Mar 27 '18 at 19:55
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    I think this is probably your map: trove.nla.gov.au/work/17038271?selectedversion=NBD24208831 Its extents would appear to be: E 37°18' 00" to E 37° 19' 00" S 0°08'30" to S 0° 09' 30" Which at least gives you lat/lon corner points. – nhopton Apr 11 '18 at 19:02

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