id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
6715	Use `ST_distance_sphere` as default instead of `ST_distance_spheroid` for geodetic distance calculations.	jbronn	jbronn	"As brought up by kmishler in this [http://groups.google.com/group/django-users/browse_thread/thread/b1e2d68034400987/8fb4beeb99b2505f#8fb4beeb99b2505f django-users thread about GeoDjango geodetic distances], `ST_distance_sphere` performs faster than `ST_distance_spheroid`.  My informal tests suggest that using `ST_distance_sphere` yields results ~30-40% faster that are a maximum of 0.25% less accurate.  

The attached patch changes the default to `ST_distance_sphere` -- spheroid calculations may be enabled by setting the `distance_spheroid` keyword to `True` in the geographic model definition (e.g., `point = models.PointField(distance_spheroid=True)`).  I haven't committed this yet because I wanted to solicit comments on whether there's a better way to do this."		closed	GIS	gis		fixed	gis distance geodetic geographic sphere spheroid		Design decision needed	1	0	1	0	0	0