2011/3/9 Dan Lyke <[email protected]>: > 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".
Which projection are you using for the project? I get the correct numbers in meters using the same projection as in the layer (EPSG: 2226). r15395M from qgis.org repo in Ubuntu 10.10, which otoh is doing lots of weird things like speaking to me in english and not opening old projects. Goyo > > 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 > _______________________________________________ > Qgis-user mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/qgis-user > _______________________________________________ Qgis-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/qgis-user
