[Qgis-user] NewbieQ: Measurement tool weirdness?

[Dan Lyke]

I'm running QGIS compiled from Subversion this morning, with support
libraries as provided by Ubuntu 10.10. I'm having a bit of trouble
figuring out the measuring tool. Short version: To get numbers that
seem to make sense I have to click of "Ellipsoidal", and then get what
look like right numbers in feet, but they're labeled "degrees".

Long version follows:

I downloaded the "Parcels" shapefile data from
https://gis.sonoma-county.org/catalog.asp

Empty project, added PAR_PARCELS.shp as a layer. Right click on the
layer, search for APN 008-454-003 (my house), click the "Zoom to
Selection" icon.

Select the line measurement tool, measure the front side of my lot, get
273.71km (it should be 52 feet, or 15.85 meters). Okay, I've clearly
got a projection issue. Open up the Layer Properties box, see:

   -  * Generated CRS (+proj=lcc +lat_1=38.33333333333334
  +lat_2=39.83333333333334 +lat_0=37.66666666666666 +lon_0=-122
  +x_0=2000000 +y_0=500000.0000000001 +ellps=GRS80 +datum=NAD83
  +to_meter=0.3048006096012192 +no_defs)

Which to my untutored eye seems right (ie: the lat and lon numbers
aren't completely whack). But I can try "Specify CRS", and I put in

  NAD83/California zone 2 (ftUS) EPSG:2226 208

(EPSG:2226 is what looks right when I manipulate this data with other
tools, like Python and Mapnik). Now it seems to be measuring 269.101km.
And the back of the lot (the assessor's office tells me this is
rectangular) measures 5,781.169km. 

If I click off the "Ellipsoidal" check box then I get a number that's
closer to what I expect, but it's labeled "degrees".

Can anyone point me to what I should be reading to explain this?

Thanks.

Dan