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How would I georeference the image below. All I have is the information provided on the Image below (showing easting and northings). I am focusing on Georeferencing the section In red. Once Georeferenced I was going to create a polygon shape around the area to act as the new shapefile. I am using ArcGIS V10.6.1

enter image description here

The only Lat and Long I have is for the center of the area

enter image description here

I need the area to be in the black box in the image below

enter image description here

Am I Georeferencing correctly as seen below?

enter image description here

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    You could draw the lines connection your border coordinates using any image manipulation software, then use the crosses to georeference, save the points and reference the original image.
    – Erik
    Aug 24, 2021 at 8:05
  • @Erik has a solution, but it depends on line of latitude and longitude on the map being straight, which they might not be if its something like a conical projection. But it all looks pretty straight and square. Join the edges and see.
    – Spacedman
    Aug 24, 2021 at 8:13
  • is this the only way or is there a way to do this without the image manipulation software?
    – Louis Tate
    Aug 24, 2021 at 8:14
  • Im not sure what you mean by join the edges? could you please provide a step by step guide
    – Louis Tate
    Aug 24, 2021 at 8:14
  • I just realized that the blue hashed area seems to be a Natura 2000 site. Get the official data on those and reference using the corners.
    – Erik
    Aug 24, 2021 at 8:19

2 Answers 2

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The problem is that you know the longitude of the first tick mark on the top, but not the latitude. Its a bit higher than 54:20N but you don't know how much. The same problem occurs for the latitude markers on the sides.

But if you connect the tick markers you can then get the lat and long of the intersections. Here's how it looks with some horizontal and vertical rulers added using GIMP:

enter image description here

Now if I add points at those intersections I know their lat-long and I can use the georeferencer as normal. Note this assumes the lines of latitude and longitude are straight and at right angles - which might not be true if this is a something like a conical map projection, but then you'd probably notice that the rectangles of the grid created weren't true rectangles.

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  • Would I need to convert the Northing and Eastings into Lat/long before georeferencing or could I just input the Northing/Eastings?
    – Louis Tate
    Aug 24, 2021 at 8:24
  • I can only see latitudes and longitudes - the only "conversion" you need to do is convert 54 degrees and 20 minutes into 54.3333 decimal degrees (and do the same for the other) if your georeferencer only accepts decimal degree input.
    – Spacedman
    Aug 24, 2021 at 8:25
  • Im very new to georeferencing, why would I change 54.20 into 54.3333?
    – Louis Tate
    Aug 24, 2021 at 8:37
  • On your map, the text 54°20'N means 54 degrees and 20 minutes north of the equator. A minute is 1/60th part of a degree, so 20 minutes is one third of a degree. In decimal, that is 0.3333 recurring. So in decimal degrees that latitude is 53.3333. I don't know if the georeferencing software you plan to use wants you to type degrees and minutes or decimal degrees, but if its decimal degrees you need to enter 53.3333 and not 53.20.
    – Spacedman
    Aug 24, 2021 at 8:42
  • Ok this makes alot of sense, thankyou. The projection I am using is ED50 31N, which I believe is Meters not decimals. I am also going to georeference on ArcGIS V10.6.1 Which allows me to add xy point data on a map
    – Louis Tate
    Aug 24, 2021 at 8:48
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After research I have found that OSPAR have a marine protected areas network with downloadable shapefiles.

https://odims.ospar.org/en/submissions/ospar_mpa_2021_07/

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