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I have a tiff that I pulled from a PDF file. It consists of a scale bar, an NTS mapsheet number, a north arrow, a scale bar, a scale, 1 line of latitude, and 1 line of longitude. I want to georeference this image. to the proper scale.

Furthermore, this image has lines of contour that I plan to vectorize using the ArcScan tool.

Can someone, in relatively easy terminology, assist me with georeferencing this image in ArcMap 10.3?

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2 Answers 2

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if you have only one line of longitude an one line of latitude than you probability need some reference map with at least few objects in common with the map which you want to georeference to do the georeferencing by objects. Other option is to find map corner coordinates based on the NTS mapsheet number and georeference using 4 map corners and cross point of two of your lon/lat lines. 3rd option would be to calculate coordinates of some objects based on scale of the map starting from lat/lon lines. it is tricky and I believe that it wont give you very well georeferenced map in the end. But you can try if you don't have any ither option.

here is nice video how to georeference in ArcGis: https://youtu.be/cv6ItuMpnyM

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  • So, I can define the coordinates of a point where the lat/long lines meet. I can get a second point by travelling some distance along a lat or long line, using the scale bar. I can then convert that to decimal degrees and have a second point in terms of coordinates. Then I have two points in terms of coordinates. Also, the map has a north arrow. Can I use those two points to then spatially reference the map easily in ArcGIS? The extent of the map is, unfortunately, arbitrary and does not reference anything (like an NTS square). .
    – Josh W
    Jan 14, 2017 at 20:50
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I'm not sure if this is the easiest, most efficient, or most accurate way, but it has worked for me and the application I am using it for. I followed the instructions in this video. I had two points on my map: a) the first one is where the lines of lat/long intersected; b) the second point is a point that lies along the line of longitude.

In photoshop, I measured a distance and converted this using the scale bar present on the map. I then converted this ground distance to a decimal degrees distance (I know, I know). I was then able to convert the decimal degrees to a DMS coordinate. At this point I had two spatially referenced points on the map. Using the youtube video, I georeferenced those points and it worked surprisingly well. I will be doing this with more maps to come (and some with less information!)

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