[Qgis-user] distance calculation

[Lee Hachadoorian]

On 07/26/2013 02:32 PM, Frazier, Tyler James wrote:
> I have 2000 polygons and want to set a field with the distance for each polygon from the center (monocentric theory)  is there a simple way to do this in QGIS? thanks, Ty
>

Vector→Analysis Tools→Distance Matrix

The function requires point geometry, but will not automatically 
calculate centroids, so you will have to calculate centroids first. The 
Standard NxT matrix will calculate distances between all possible pairs 
of points. If your purpose is related to monocentric city theory, you 
need to choose one point as your center and export it to a new dataset 
with only one feature.

Remember that distance calculations will be in the project CRS, so 
choose an appropriate one (i.e., don't leave in default 4326 or you will 
get distances in decimal degrees, which is essentially useless).

Best,
--Lee

-- 
Lee Hachadoorian
Assistant Professor in Geography, Dartmouth College
http://freecity.commons.gc.cuny.edu