Clustering / Grouping points

1,376 views
Skip to first unread message

mhakk...@mvcc.vic.gov.au

unread,
Jul 23, 2014, 12:11:33 AM7/23/14
to australian-qg...@googlegroups.com
Hi,

Just wondering if anyone has clustered / grouped a point layer?

I have used the Raster > Heatmap tool with some great results, but wanted to try clustering/grouping points based on their spatial proximity to each other.

I was hoping to achieve something similar in QGIS compared to the following systems:


Regards,
Michael Hakkennes
Moonee Valley City Council

Nathan Woodrow

unread,
Jul 23, 2014, 1:02:24 AM7/23/14
to australian-qg...@googlegroups.com
Hey Michael,

This is a planned feature. Martin (one of the core devs) has it on his todo list. Not sure about ETA, or funding status of that though.

Regards,
Nathan


--
You received this message because you are subscribed to the Google Groups "Australian and New Zealand QGIS User Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email to australian-qgis-use...@googlegroups.com.
To post to this group, send email to australian-qg...@googlegroups.com.
Visit this group at http://groups.google.com/group/australian-qgis-user-group.
To view this discussion on the web, visit https://groups.google.com/d/msgid/australian-qgis-user-group/2059d4a8-bfd3-493e-a63c-ddcf16f6132d%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

Andy Tice

unread,
Jul 23, 2014, 4:00:10 AM7/23/14
to Unname
Hey Nathan/Michael,
Just thought I'd chime in with another suggestion on cluster / point analysis. 
There's a pugin called ClusterPy (http://www.rise-group.org/risem/clusterpy/index.html) which I've had some limited success with - it tends to be a bit buggy, though.

One of my biggest ... biggest wishes, though, would be for some dev to be able to implement Stan Openshaw's Geographical Analysis Machine in QGIS. There is an R implementation of it (http://artax.karlin.mff.cuni.cz/r-help/library/DCluster/html/opgam.html) and also a stand alone Java version (https://code.google.com/p/spatial-cluster-detection/) - although this needs compiling to get running (it is Creative Commons, though)

It's just a, wish list at the moment (and I've not got funding to get this going) ... but,  having something like this working directly in QGIS would be brilliant.

Cheers,
Andy

clusterPy


Andy Tice

unread,
Jul 23, 2014, 4:18:52 AM7/23/14
to Unname
Again, sorry!
On a practical note, what you could do for a quick n' dirty approach is:

1. Buffer your point layers (a buffer for each point) to the desired distance 
2. Run a point in polygon (Vector->Analysis Tools -> Points in Polygon) count using the resulting buffer layer - this will give you a new file with a column called PNTCNT - this is the count of points within the buffer radius first set.

Depending on how complex your point layer is, the second step can take a few minutes to run.... so you'll have to be patient!
I recently used this process to produce this map (https://flic.kr/p/o8FaNk), it took about 5 minutes to run the point in polygon count with approximately 10,000 points .
Cheers,
Andy


On Wed, Jul 23, 2014 at 2:11 PM, <mhakk...@mvcc.vic.gov.au> wrote:
Reply all
Reply to author
Forward
0 new messages