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Is there a way in ArcGIS Desktop 10.4 to 'unfold' (reshape/modify) feature classes, e.g. a polygon of a circular city, to make them look similar to a Mercator or plate carrée projection of Antarctica, i.e. opened out into a strip at the bottom of a map? Distortions away from the feature of interest are fine.

This is my specific example: I have a polygon of an almost circular city and other feature classes showing transport links into the city's periphery. Rather than producing a map with the empty polygon of the city in the centre of the map, I would like to unfold the city's polygon and turn it into a strip at the bottom of the map with all the other feature classes extending upwards from this strip. I want the city and its periphery to look similar to how Antarctica is displayed on maps with a Mercator or plate carrée projection. This question is not about changing the projection of a data file.

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This task sounds similar to a map called "An Unfurling of Lake Michigan" by cartographer Daniel Huffman. He took the edge of lake Michigan and split it into skewed quadrilaterals, then straightened each into a rectangle and stacked them next to each other. He has a blog post describing the process, including his python script, here: https://somethingaboutmaps.wordpress.com/2015/09/28/a-matter-of-perspective/

Here are some of his great graphics depicting the process:

Michigan unfurling workflow

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This is untested but I think could work:

  1. Identify the coordinate systems used for the two displays of Antarctica that you present.
  2. Determine the extent of the left hand view of Antarctica
  3. Use spatial adjustment (affine) to move your city feature class into the same extent as the left hand view of Antarctica
  4. Define your city feature class to have the same coordinate system as the left hand view of Antarctica
  5. Project your city feature class from the coordinate system of the left hand view of Antarctica to the coordinate system of the right hand view of Antarctica

If it works for Antarctica then I think it should work for any polygon with similar coordinate values to Antarctica using the same two coordinate systems.

  • I'm going to try out your suggestion as well. What do you mean by 'left-hand/right-hand view of Antarctica'? – MaikS Mar 27 '18 at 14:28
  • They refer to your picture. – PolyGeo Mar 27 '18 at 20:09

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