[GRASS-dev] [GRASS GIS] #942: v.univar: please add support for geometry statistics

#942: v.univar: please add support for geometry statistics
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Reporter: neteler | Owner: grass-dev@lists.osgeo.org
     Type: enhancement | Status: new
Priority: normal | Milestone: 7.0.0
Component: default | Version: svn-trunk
Keywords: vector, statistics | Platform: Unspecified
      Cpu: Unspecified |
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It would be great to have (via flag?) the possibility to generate the
univar stats of x,y[,z] point geometry for analysing optimal random
sampling,
interpolation and such. Support for points might be sufficient for most
cases. Perhaps heuristics are sufficient (like in the lidar tools in GRASS
7).

thanks, Markus

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Ticket URL: <http://trac.osgeo.org/grass/ticket/942&gt;
GRASS GIS <http://grass.osgeo.org>

#942: v.univar: please add support for geometry statistics
--------------------------+-------------------------------------------------
  Reporter: neteler | Owner: grass-dev@lists.osgeo.org
      Type: enhancement | Status: new
  Priority: normal | Milestone: 7.0.0
Component: default | Version: svn-trunk
Resolution: | Keywords: vector, statistics
  Platform: Unspecified | Cpu: Unspecified
--------------------------+-------------------------------------------------
Comment (by hamish):

''really'' dumb and inefficient emergency workaround:
  * g.region rows=1 cols=1
  * r.in.xyz x=1 y=2 z=1 out=x_mean
  * r.univar x_mean
etc

or just use v.out.ascii + awk.
see this script for calc'ing the mean:
   source:grass-addons/vector/v.points.cog/v.points.cog

that script could probably get a flag to also output numbers for
variance,stddev without too much work.

Hamish

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Ticket URL: <https://trac.osgeo.org/grass/ticket/942#comment:1&gt;
GRASS GIS <http://grass.osgeo.org>

#942: v.univar: please add support for geometry statistics
--------------------------------+-------------------------------------------
Reporter: neteler | Owner: grass-dev@…
     Type: enhancement | Status: new
Priority: normal | Milestone: 7.0.0
Component: Default | Version: svn-trunk
Keywords: vector, statistics | Platform: Unspecified
      Cpu: Unspecified |
--------------------------------+-------------------------------------------

Comment(by wenzeslaus):

Does the following helps?

Pietro Zambelli in [http://lists.osgeo.org/pipermail/grass-
dev/2014-January/066819.html Object-based image classification in GRASS]
at grass-dev ([http://osgeo-org.1560.x6.nabble.com/Object-based-image-
classification-in-GRASS-td5086693.html nabble]):

v.stats r58637 => Extract statistics from a vector map
        (statistics about shape and about raster maps).
        v.stats internally use (in grass-addons):
         - v.area.stats r58636 => extract some statistics about
           the shape (in grass-addons);
         - v.to.rast => re-convert the vector to a raster map using the
           vector categories to be sure that there is a correspondence
           between vector and raster categories (zones).
         - r.univar2 r58439 => extract some general statistics from
           raster using the zones (consume much less memory than
           r.univar, and compute more general statistics like:
           skewness, kurtosis, and mode (in grass-addons);

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Ticket URL: <https://trac.osgeo.org/grass/ticket/942#comment:2&gt;
GRASS GIS <http://grass.osgeo.org>

#942: v.univar: please add support for geometry statistics
--------------------------+-------------------------------------------------
  Reporter: neteler | Owner: grass-dev@…
      Type: enhancement | Status: closed
  Priority: normal | Milestone: 7.0.0
Component: Default | Version: svn-trunk
Resolution: fixed | Keywords: vector, statistics
  Platform: Unspecified | Cpu: Unspecified
--------------------------+-------------------------------------------------
Changes (by neteler):

  * status: new => closed
  * resolution: => fixed

Comment:

This got solved long time ago:

http://grass.osgeo.org/grass70/manuals/v.univar.html

-d Calculate geometry distances instead of table data

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Ticket URL: <http://trac.osgeo.org/grass/ticket/942#comment:3&gt;
GRASS GIS <http://grass.osgeo.org>