[GRASS-user] Using r.quantile result with r.recode

Glynn Clements glynn at gclements.plus.com
Tue Apr 16 12:50:41 PDT 2013

[CC to grass-dev for discussion]

Pedro Venâncio wrote:

> Thank you very much for your answer!
> My question lies precisely in the need to know if a quantile value
> which falls as the upper limit for one range and the lower limit of
> the next, should belong to the class anterior or posterior.
> For example, assuming that r.quantile (with -r flag) gives this result:
> 2:6:1 
> 6:8:2 
> 8:12:3 
> 12:20:4 
> 20:873:5
> the value 6 should belong to the first class or second?

r.recode will treat boundary values as belonging to the upper range,
e.g. in the above example, 6.0 will get recoded to 2.

This behaviour stems from Rast_fpreclass_get_cell_value() in
lib/raster/fpreclass.c, and isn't configurable (i.e. there's no way
that r.recode's behaviour could be modified without modifying the
fpreclass functions).

Glynn Clements <glynn at gclements.plus.com>

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