Trying to get a handle on the measuring tool. My original data is
geographic coordinates, WGS-84, in a PostGIS database. "On the fly
projection" is enabled. QGIS 1.0.1 on Debian.
I would *like* to display data in geographic coordinates (ie., display
in lat. and lon.) but measure in feet. (It's a utility application
targeted at American linemen.)
I've also created a Python plugin as an alternate measuring tool. I can
place a QgsRubberBand and use QgsDistanceArea directly on those coordinates.
When the CRS is geographic coordinates (WGS-84), the default line
measuring tool returns meters. My plugin returns degrees. Both of
these are regardless of the map unit selected in project properties.
When the CRS is projected, the default line measuring tool still returns
meters. My plugin returns distance in the base unit of the projection.
Again, both are regardless of the map unit selected.
If the goal is to display in geographic coordinates with measurement in
feet -- and I'm willing to write a plugin to do it -- is there any way
to get there short of coding the calculation myself directly from the
coordinates?
I can pass the whole problem off to PostGIS to do the appropriate
coordinate conversions and get me the numbers I want if I have to, but
I'd prefer to avoid that.
Ron Bentley
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