I am working on a map of South America (from the top of Chile down to Cape Horn; everything south of 18S). I need to include distance buffers on my map but I am getting confused by which projection to use to get the distance right.

Would Plate Carree work or is there a better one for this area?


3 Answers 3


No projection is natively going to give you the correct distances unless you are measuring very particular lines, like from the center of a azimuthal equidistant projection.

If the area of interest is relatively small, a projected coordinate reference system (CRS) that's conformal (maintains local angles/shapes) or equal area may give 'good enough' results.

Some software tools or workflows may have the capability to return geodesic-based distances instead. Geodesic distances are based on the surface of the ellipsoid so still not 100% correct relative to the topography, but often good enough versus 2D Cartesian distances based on a projected CRS.

For half of South America, you could make a custom equidistant cylindrical projection. That would have accurate north-south distances and the distances along the standard parallels would be accurate. Use SIRGAS for the geographic CRS.


Follow this link to find the zone of your study area https://www.e-education.psu.edu/natureofgeoinfo/c2_p22.html


Try the projected coordinate system Peru96_UTM_Zone_17S. If that doesn't appear accurate try Peru96_UTM_Zone_18S and Peru96_UTM_Zone_19S. I hope this helps.

  • 1
    Peru is north of Chile so I don't think ProjCRS based on Peru96 are appropriate.
    – mkennedy
    Apr 1, 2019 at 20:17

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