I'm calculating field of various features in my shapefile using QGIS.
I'm getting some sample length as 0.134914579766986.
I want to know in what unit (eg: meters, km etc) is the above value ?
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I think this is a bug. The function description said " The length calculated by this function respects both the current project's ellipsoid setting and distance unit settings". My distance unit setting is "meters". The $length function return degres. My project use UTM 19 NAD83 projection, my shape is geographic (EPSG:4269). So the $length function return result in the shape unit, not in the project unit as specified in the doc. And this bug appears only in labelling. So you can create a column attribute in the shape, use $lentgh for populate all line with the length in meter (divide by 1000 f– Gilles TurgeonCommented Oct 10, 2018 at 12:58
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Welcome to GIS Stack Exchange. Please read the tour to get a sense of the workings of this site. Your post here doesn't provide an answer to the original question but rather to a comment on the original answer. This might get confusing if it is caused by a bug that gets fixed.– GabrielCommented Oct 10, 2018 at 13:32
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1 Answer
This is a measurement of whatever map units are specified in your project properties or CRS.
Check out:
http://hub.qgis.org/wiki/quantum-gis/Getting_Started_with_CRS_and_Projections
OR
Page 9 of http://wiki.osgeo.org/images/3/38/Db_foss_m1.pdf
"To set project properties click "[Settings > Project Properties]" in the main menu. The "Project Properties" window will appear. Click on the "[General]" tab and set Project Title and Map Units."
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1Funnily enough this doesn't work for the calculator in the Style tab of a layer. My project has CRS EPSG:3857 (units is meters) but my layer has EPSG:4326 (units is degrees). If I make a legend/style for the layer, the units for the $area variable is always in the CRS of the layer, not the Project CRS. Commented Jul 28, 2017 at 1:41