[GIS] Using azimuthal orthographic projection in QGIS

coordinate systemqgis

I'm trying to create a globe view in QGIS 2.6 with an Azimuthal Orthographic projection using NaturalEarth's 110m countries dataset.

I'm following Hamish Campbell's blog post instructions that have been replicated by other users (eg here).

Problem 1

Using Hamish's recommended projection parameters with my lats/longs: +proj=ortho +lat_0=36.5 +lon_0=-118.8 +x_0=0 +y_0=0 +a=6371000 +b=6371000 +units=m +no_defs to define a custom projection gives this result:

Azimuthal Orthographic attempt

Lots of artefacts – what am I doing wrong / is it a bug?.

Problem 2

But Hamish mentions the presence of artefacts (I wouldn;t have thought the sort of artefacts i'm encountering but…) and recommends using some python to clip the dataset to the circle of the globe from the projection view.

I won't reproduce the python Hamish publishes (you can view it in step 2 in his post linked above) but having saved the file as clipper.py in QGIS python path, imported into the QGIS python window (import clipper) and done clipper.doCall(iface,36.5,-118.8) I don't get a new layer generated in the map window.

Are there any obvious things I might be doing wrong?

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Best Answer

Newer versions of QGIS have 'simplified geometries' enabled by default. As a result you might get an image like this:

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To disable simplified geometries, untick the "Simplify geometries" option in the layer rendering options.

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I'll update the blog post when I can.

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