Consider the following geographic polygon in PostGIS:
POLYGON((60 -60,60 -50,179 -50,179 -60,60 -60))
The smallest latitude is -60, so initially I expected any point with a latitude less than -60 to fall outside of the polygon.
But it doesn't; a point at 136,-73 is considered to fall within the polygon:
SELECT ST_Covers(ST_GeogFromText('SRID=4326;POLYGON((60 -60,60 -50,179 -50,179 -60,60 -60))'), ST_GeogFromText('SRID=4326;POINT(136 -70)'));
After some thinking, I realised that this is because PostGIS uses great circles to form the edges of polygons, and in this case, that makes the lower edge of the polygon 'bulge out' towards the south pole.
If I view the same polygon in Google Earth, the lower edge of the polygon runs along the -60 degree parallel, so apparently Google Earth uses a different manner to connect vertices than PostGIS.
What is the name of the manner that Google Earth uses, and can I somehow make PostGIS use that same manner?