[GRASS-user] Landcover change

[Moritz Lennert]

On 22/10/13 10:56, Nikos Alexandris wrote:
> Antonio:
>
>>>> I have two landcover change maps and I wanted to know if there is any
>>>> functionality or module that allow us to compare the maps and landcovers?
>>>> (e.g. class 1 2 and 3 in both maps and identify the pixels
>>>> (Map 1 Map 2)
>>>> 1     |    1
>>>> 1     |    2
>>>> 1     |    3
>>>> 2     |    1
>>>> 2     |    2
>>>> 2     |    3
>>>> 3     |    1
>>>> 3     |    2
>>>> 3     |    3
>
> Nikos:
>
>>> Have a look at r.cross.
>
> Moritz Lennert wrote:
>
>> Or at r.report or r.stats with the two maps as input.
>
> Multiple raster maps fed to r.report! Interesting. The output is quite large
> here using two maps with (1 to) 28 or 30 classes each. I am not sure on how to
> use this ouput yet. I guess it deserves a short explanation in the manual.

I think r.report output is only useful for few classes or if you are 
looking for a specific correspondence of classes. For more advanced 
treatment of such crossing of maps, I would use r.stats, saving the 
results into a file and then any spreadsheet or other tool of your 
choice to visualize or analyze the results.

Moritz