Glynn Clements wrote:
Markus Metz wrote:
Please try the new addon v.centerpoint [0]. It calculates various
center points for point clouds, lines, and areas. Standard options are
the geometric mean (center of gravity)
That's the arithmetic mean.
The geometric mean of a set of N values is
Markus Metz wrote:
Please try the new addon v.centerpoint [0]. It calculates various
center points for point clouds, lines, and areas. Standard options are
the geometric mean (center of gravity)
That's the arithmetic mean.
The geometric mean of a set of N values is the Nth root of the
Hamish wrote:
see also the v.points.cog addons script:
http://grasswiki.osgeo.org/wiki/AddOns/GRASS_6#v.points.cog
although I haven't tried it for anything as big as lidar data.
oops, I completely forgot to mention the r.cog addon script too:
Moritz:
Would be interesting to see results for big data. And AFAIK median is a
bit more difficult to do in awk. I imagine that replacing the median by
the mean in numpy is no problem (might be a flag to add to v.median).
see the old r.univar.sh shell script for an idea of how to get a
On 22/09/13 17:06, Markus Metz wrote:
Markus Neteler wrote:
Hi,
I came across this question:
http://gis.stackexchange.com/questions/71734/how-to-calculate-mean-coordinates-from-big-point-datasets
Please try the new addon v.centerpoint [0]. It calculates various
center points for point
Markus Neteler wrote:
Hi,
I came across this question:
http://gis.stackexchange.com/questions/71734/how-to-calculate-mean-coordinates-from-big-point-datasets
Please try the new addon v.centerpoint [0]. It calculates various
center points for point clouds, lines, and areas. Standard options
Glynn Clements wrote:
Luca Delucchi wrote:
maybe v.median [0] could help?
Not for large datasets. First, it requires that the data will fit into
RAM. Second, numpy.median() sorts the entire array and takes the
middle value, which is somewhere between O(n.log(n)) for the typical
case and
On Fri, Sep 20, 2013 at 5:38 PM, Markus Metz
markus.metz.gisw...@gmail.com wrote:
Glynn Clements wrote:
Luca Delucchi wrote:
maybe v.median [0] could help?
Not for large datasets. First, it requires that the data will fit into
RAM. Second, numpy.median() sorts the entire array and takes
On 18/09/13 16:24, Markus Metz wrote:
On Wed, Sep 18, 2013 at 11:41 AM, Moritz Lennert
mlenn...@club.worldonline.be wrote:
On 18/09/13 10:51, Luca Delucchi wrote:
On 17 September 2013 22:10, Markus Netelernete...@osgeo.org wrote:
Hi,
I came across this question:
On Thu, Sep 19, 2013 at 9:15 AM, Moritz Lennert
mlenn...@club.worldonline.be wrote:
On 18/09/13 16:24, Markus Metz wrote:
Moritz Lennert wrote:
Here's a little test:
$time v.median in=elev_lid792_randpts
638648.50|220378.50
Should be 638648|220378. It seems that numpy gets the
On Thu, Sep 19, 2013 at 2:32 PM, Markus Metz
markus.metz.gisw...@gmail.com wrote:
...
I am not sure. For areas without isles, there is a faster alternative.
For areas with isles, the current approach is fast, but the centroids
might be placed at somewhat unexpected locations (the next best
Luca Delucchi wrote:
maybe v.median [0] could help?
Not for large datasets. First, it requires that the data will fit into
RAM. Second, numpy.median() sorts the entire array and takes the
middle value, which is somewhere between O(n.log(n)) for the typical
case and O(n^2) for the worst case
On 18/09/13 00:10, Markus Neteler wrote:
Hi,
I came across this question:
http://gis.stackexchange.com/questions/71734/how-to-calculate-mean-coordinates-from-big-point-datasets
and wondered if this approach would be the fasted:
# http://grass.osgeo.org/sampledata/north_carolina/points.las
On 17 September 2013 22:10, Markus Neteler nete...@osgeo.org wrote:
Hi,
I came across this question:
http://gis.stackexchange.com/questions/71734/how-to-calculate-mean-coordinates-from-big-point-datasets
and wondered if this approach would be the fasted:
#
On 18/09/13 10:51, Luca Delucchi wrote:
On 17 September 2013 22:10, Markus Netelernete...@osgeo.org wrote:
Hi,
I came across this question:
http://gis.stackexchange.com/questions/71734/how-to-calculate-mean-coordinates-from-big-point-datasets
and wondered if this approach would be the
On Wed, Sep 18, 2013 at 11:41 AM, Moritz Lennert
mlenn...@club.worldonline.be wrote:
On 18/09/13 10:51, Luca Delucchi wrote:
On 17 September 2013 22:10, Markus Netelernete...@osgeo.org wrote:
Hi,
I came across this question:
Hi,
I came across this question:
http://gis.stackexchange.com/questions/71734/how-to-calculate-mean-coordinates-from-big-point-datasets
and wondered if this approach would be the fasted:
# http://grass.osgeo.org/sampledata/north_carolina/points.las
v.in.lidar input=points.las
Markus Neteler wrote:
I came across this question:
http://gis.stackexchange.com/questions/71734/how-to-calculate-mean-coordinates-from-big-point-datasets
so wants to find the average coordinate?
and wondered if this approach would be the fasted:
#
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