[Qgis-developer] QGIS defaulting to no ellipsoid - Bug #7441, opinions needed

[Nyall Dawson]

I'm posting this comment to the list to hopefully get some more
opinions about bug 7741 - "Measurements in degrees even when meters
are chosen as map units"

I think this bug is caused by QGIS defaulting to "None / planimetric"
for the ellipsoid for new projects. In 1.8 QGIS defaulted to WGS84.
IMO The correct behaviour should be to restore this as the default
setting.

However -- I'm having lots of trouble understanding how this is
supposed to work. The option to choose a canvas unit for a project is
under the "Canvas units (CRS transformation: OFF)" group in the
project properties dialog. If you hover over an option the tooltip
states "Used when CRS transformation is turned off". I'm pretty sure
this tooltip is wrong -- since the choice DOES apply even if CRS
transformation is turned on. HOWEVER, the choice is reset when the
project properties window is opened UNLESS CRS transformation is
off.... very confusing!!

To add to the confusion there's 2 "WGS84" ellipsoids listed - one is
"WGS84" and one is "WGS 84". Choosing "WGS84" actually results in
"Clarke 1986" being saved for the project!

My gut feeling is that:
- Ellipsoid should default to "WGS 84"
- The duplicate/bad "WGS84" ellipsiod needs to be removed
- The tooltip for canvas units needs to be fixed/reworded
- The choice of canvas unit should save even if CRS transformation is enabled

I'd like a second opinion on this though, since there may have been
discussion around this behaviour which I'm not aware of.

Nyall