Re: [GRASS-user] Identify duplicate points

2018-09-25 Thread Moritz Lennert

On 24/09/18 17:05, Markus Neteler wrote:

On Fri, Sep 21, 2018 at 1:13 PM Johannes Radinger
 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

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Re: [GRASS-user] Identify duplicate points

2018-09-24 Thread Markus Neteler
On Fri, Sep 21, 2018 at 1:13 PM Johannes Radinger
 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
?

HTH,
Markus
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[GRASS-user] Identify duplicate points

2018-09-21 Thread Johannes Radinger
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?

cheers,

/Johannes
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