[Qgis-user] Measuring unit of $lenght / Unidad de medida de $lenght

[Andre Joost]

Am 20.09.2012 19:37, schrieb Pablo Schweitzer:
> Thanks Alex...
> Perhaps the unit of measurement is "degrees". In Ecuador the circumference of
> the earth is 40,076 km. 40076/360 ° = 109.79. But the equivalence degrees =
> km varies with latitude and longitude. So use a conversion factor is very
> difficult in large countrys lake Argentina :-(
>
> In
>
> You can change the unit of measure?
>

It just depends on the Coordinate reference Systems (CRS) you use.

WGS84 lat/lon ist in degrees, and most projected CRS are in meters (or 
feet in some countries). Only Google Mercator has no real unit of mesure.

You can have a layer in lat/lon CRS, but the project set to a projected 
CRS using metres (checking "on-the-fly-projection" in settings/Project 
Settings). Measuring is always done in the *project* CRS. Just check out 
what projected CRS is common in your country. At least UTM (with correct 
Zone) applies world wide.

HTH,
Andre Joost