[GRASS-user] Check if a raster map has any valid pixel

GRASS GRASS user
1

Greetings
I have a python script where I need to check if an input raster map has any valid pixel (at least one pixel that is not null). How can I check this (easy and quick way?) in order to be integrated in my Script?

Thjanks
Kim

2

Kim Besson wrote:

I have a python script where I need to check if an input raster map has any
valid pixel (at least one pixel that is not null). How can I check this
(easy and quick way?) in order to be integrated in my Script?

Check the range:

  $ r.mapcalc --o 'foo = null()'
  $ r.info -r foo
  min=NULL
  max=NULL

The range can only have min=max=NULL if there are no non-null cells.

--
Glynn Clements <glynn@gclements.plus.com>

3

Thank Glynn. But how can I retrieve min and max using a Python Script?

2010/10/25 Glynn Clements <glynn@gclements.plus.com>

Kim Besson wrote:

I have a python script where I need to check if an input raster map has any
valid pixel (at least one pixel that is not null). How can I check this
(easy and quick way?) in order to be integrated in my Script?

Check the range:

$ r.mapcalc --o ‘foo = null()’
$ r.info -r foo
min=NULL
max=NULL

The range can only have min=max=NULL if there are no non-null cells.

–
Glynn Clements <glynn@gclements.plus.com>