[Qgis-developer] Ellipsoid for distance calculations (confusing items in combo)

[Alexander Bruy]

Hi devs,

working with measure tools I found that "Ellipsoid for distance calculations"
combobox from Map tools tab in QGIS options (Settings - Options) has
duplicates. For example, there are tree WGS84 and two Clarke 1866 ellipsoids.

I look at code, then at default srs.db and here is what's I found. In
srs.db we have
two ellipsoids with similar names and different acronyms

acronym         | name      | radius               | parameter2
WGS84          | WGS 84 | a=6378137.0      | rf=298.257223563
IGNF:ELG053 | WGS84  | a=6378137.0000 | rf=298.2572235630000

same for Clarke 1866 ellipsoids

acronym         | name           | radius                | parameter2
clrk66             | Clarke 1866  | a=6378206.4      | b=6356583.8
IGNF:ELG004 | Clarke 1866  | a=6378206.4000 | rf=294.9786982000000

Combobox filled with values forom "name" column and this leads to
duplicate (or very similar) items. Maybe it is better to display ellipsoids
as "name - acronym" to avoid confusing? Or even remove this duplicate
entries from srs.db?

Also there is another problem. When "Ellipsoid for distance calculations"
compo populated first of all added "None / Planimetric" item, after that
values from srs.db. And finally "None / Planimetric" item is replaced with
ellipsoid stored in settings here "/qgis/measure/ellipsoid". This replacement
created duplicate entry of any ellipsoid, saved as default. For example, if
I save "Airy 1830" as default and then close options dialog and open it again
I'll get two "Airy 1830" entries in combo.
I don't understand is this replacement necessary, maybe it should be removed?

Thanks
-- 
Alexander Bruy