[GRASS-dev] [GRASS GIS] #3190: Define colors in bivariate scatterplot according to third raster layer

GRASS GIS trac at osgeo.org
Sat Oct 22 11:10:57 PDT 2016

#3190: Define colors in bivariate scatterplot according to third raster layer
  Reporter:  pvanbosgeo   |      Owner:  grass-dev@…
      Type:  enhancement  |     Status:  new
  Priority:  normal       |  Milestone:  7.0.6
 Component:  Default      |    Version:  unspecified
Resolution:               |   Keywords:
       CPU:  Unspecified  |   Platform:  Unspecified

Comment (by wenzeslaus):

 This should be relatively easy for G7:d.correlate. How hard would be to
 add it to the GUI (like G7:d.histogram) is another thing. I'm not sure how
 about the wx-based scatter plot which is what you mean I suppose.

 But since you asked, I finished `r.scatterplot` in r69716 which is derived
 from `r3.scatterplot` and creates the scatter plot as vector map with
 points, see:


 A scatter plot as vector points as opposed to an image has some pros and
 cons. Some of the pros for the user are: you can measure and query in the
 "image" using (all) the normal tools, visualize with full vector
 visualization tool set, further select from the data, and you can
 processes the data (to e.g. bin it). A significant con is (lower) speed
 (if nothing else, you first iterate over the data to create the vector and
 then once again to draw).

 Here is an example result from the manual page:


 This concept is basically what is in R or Matplotlib where the spatial
 data are often drawn using the originally non-spatial displays, here we
 convert the non-spatial to spatial and use the spatial data display.

Ticket URL: <https://trac.osgeo.org/grass/ticket/3190#comment:1>
GRASS GIS <https://grass.osgeo.org>

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