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Is it possible to use the Goode Homolosine projection in QGIS? Both QGIS and GRASS seem to have trouble with the interruptions, squashing the higher latitudes together. I tried +proj=goode +ellps=sphere +datum=wgs84 as a custom CRS.

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2 Answers

up vote 1 down vote accepted

There has been a question on interrupted projections before: Discontinous or Interrupted map projections?

The conclusion was that proj4 (which is used for projection handling in QGIS and GRASS) does not support interrupted projections.

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I should have mentioned a ticket on the Proj.4 tracker for Goode Homolosine support (which was created after that question was asked): trac.osgeo.org/proj/ticket/106. Looks like I don't have as new a proj as I thought, though; I'll try updating my proj and see how it goes. Sorry for the duplicate question. –  mattwigway Nov 26 '11 at 16:11
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With QGIS Lisboa, there is now a basic support for Goode Homolosine projection.

I downloaded IGH data from http://edc2.usgs.gov/glcc/fao/data_specifications.php

and set up this user CRS:

+proj=goode +lon_0=-100 +x_0=-11119487.43 +y_0=0 +a=6370997 +b=6370997 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs

for North America.

lon_0 and x_0 are from Appendix 03 of this document: http://proceedings.esri.com/library/userconf/proc98/proceed/TO850/PAP844/P844.HTM

Overlaying natural Earth world boundaries_m, I get this picture:

enter image description here

Fitting good in North America (about 20km misplaced), and distorted in other regions.


EDIT

Just noticed that proj knows interrupted goode homolosine by now:

+proj=igh +ellps=sphere +towgs84=0,0,0 +lon_0=100w +x_0=-11119487.43

gives me this picture of Natural Earths world boundaries and a 10-degree-vector grid:

enter image description here

I'm not sure which parameteres apart from +proj=igh are necessary anymore.

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