[GRASS-user] Identify duplicate points

[Moritz Lennert]

On 24/09/18 17:05, Markus Neteler wrote:
> On Fri, Sep 21, 2018 at 1:13 PM Johannes Radinger
> <johannesradinger at gmail.com> wrote:
>> Hi all,
>>
>> this is maybe a very easy question: But how is it possible to identify duplicate points (that have the same pair of coordinates) of a set of points. I'd like to get the categories of all non-single (i.e.duplicate/triplicate etc.) points. I know that I could use the 'rmdupl' tool from v.clean to remove duplicate geometries but I'd rather like to manually select the duplicate points I'd like to remove. Therefore, I'd need to identify the points with similar geometries first. I thought of using v.distance to get the all points that have 0 distance from another point but the result is 0 for all points (due to the self-distance which is 0 of course). I could update the X,Y coordinates of each point and the use a SQL command to identify points with similar coordinate pairs; however, is there a more direct way or tool in GRASS to perform such a task?
> 
> Did you see
> https://grasswiki.osgeo.org/wiki/Find_multiple_points_in_same_position
> ?


If these solutions do not satisdy you, you could also try v.distance -a 
with a very low dmax.

Moritz