[GRASS-user] using r.mapcalc on a 100 rasters to produce one output (a temporal set of rasters)

GRASS GRASS user
1

My apologies if this is a repeat post, but i think my question did not get delivered last try. (I’m new here!)

I am looking for a way for GRASS to do create one output raster based on the analysis of say 100 rasters (same spatial coordanates, but each raster has an equal time interval between them).
For example if I have 100 rasters that have only 0’s and 1’s, and I want to calculate an output raster that shows how long it took each cell to first acquire a value of 1. Another example: sums up all 100 rasters to one output raster.

From what I’ve gathered, I think that r.mapcalc will do the necessary functions, but I cannot find an example where it is processing 100s of rasters in a temporal set.
Am I correct in assuming that r.mapcalc is the best solution for my problem? Are there other functions I should know about? Is there any examples that are similar to my problem?

Thank you for you advice
a.o.

2

On Thu, Aug 19, 2010 at 2:50 AM, m k <ytrapaet@hotmail.com> wrote:

My apologies if this is a repeat post, but i think my question did not get
delivered last try. (I'm new here!)

I am looking for a way for GRASS to do create one output raster based on the
analysis of say 100 rasters (same spatial coordanates, but each raster has
an equal time interval between them).

For example if I have 100 rasters that have only 0's and 1's, and I want
to calculate an output raster that shows how long it took each cell to first
acquire a value of 1. Another example: sums up all 100 rasters to one output
raster.
From what I've gathered, I think that r.mapcalc will do the necessary
functions, but I cannot find an example where it is processing 100s of
rasters in a temporal set.

The r.series module is the right tool for this:
http://grass.osgeo.org/grass64/manuals/html64_user/r.series.html

I have added some hints to
http://grass.osgeo.org/wiki/Time_series

Markus

3

m k wrote:

My apologies if this is a repeat post, but i think my question did not get
delivered last try. (I'm new here!) I am looking for a way for GRASS to do
create one output raster based on the analysis of say 100 rasters (same
spatial coordanates, but each raster has an equal time interval between
them). For example if I have 100 rasters that have only 0's and 1's, and I
want to calculate an output raster that shows how long it took each cell
to first acquire a value of 1. Another example: sums up all 100 rasters to
one output raster.

>From what I've gathered, I think that r.mapcalc will do the necessary
>functions, but I cannot find an example where it is processing 100s of
>rasters in a temporal set.Am I correct in assuming that r.mapcalc is the
>best solution for my problem? Are there other functions I should know
>about? Is there any examples that are similar to my problem?

You can use "r.mapcalc" to achieve (almost) everything. Yet, for time-series,
you can use the module "r.series".

Have also a look at <http://grass.osgeo.org/wiki/Time_series&gt;

Regards, Nikos