[GRASS-dev] Descriptions for r.colors color rules

[Hamish]

--- Helena Mitasova <hmitaso at unity.ncsu.edu> wrote:


> Eric Patton wrote:
> > I was updating the r.colors docs, as the given rules in the html  
> > are out of sync with the program.
> > I'm not sure how to describe some of the canned rules, particularly
> > curvature and evi.
> >
> > Anyone know what these color tables were intended to map?

Helena:
> curvature is for terrain curvatures (based on the color table that  
> you get for curvatures
> from v.surf.rst and r.slope.aspect), something like this
> http://skagit.meas.ncsu.edu/~helena/wrriwork/lakewh/honpc.jpg
> http://www.grassbook.org/gallery/chapters/s060806f010_pcurv.jpg
> http://www.grassbook.org/gallery/chapters/s0609f020_topoanal.jpg
> 
> negative values are blues, positive values are yellow to red (I will 
> double check that to make sure).
> Generally it is useful for maps that have both positive
> and negative values.

see also r.colors.stddev from the wiki addons page. To me it is a very
interesting module for setting color tables for difference maps etc.

> I don't know about evi,

It is enhanced vegetation index from eg MODIS data like NDVI.
see  http://earthobservatory.nasa.gov/Library/MeasuringVegetation/


Hamish



      ____________________________________________________________________________________
Looking for last minute shopping deals?  
Find them fast with Yahoo! Search.  http://tools.search.yahoo.com/newsearch/category.php?category=shopping