[GRASS-user] How to add labels to raster non-interactively?

[Rainer M Krug]

Glynn Clements wrote:
> Rainer M. Krug wrote:
> 
>> I have a raster which has very large cell values (>10^10) which I can 
>> not store in the grid directly.
> 
> Do you have to use integers? A DCELL (double-precision floating point)
> map can store integers up to 2^53 (~10^16) exactly.

No - I don'y have to use integers - DCELL would be fine as well. but how 
can I change the format? The raster is created from an imported shape file.
In a second step I want to use r.reclass() to create the second raster 
which holds the large cell values. Can I specify in r.reclass() that the 
cell values should be stored as DCELL?

> 
>> Therefore I have at the moment category 
>> values of 1-6 and 1 represents 10^10. As I want to use mapcalc with 
>> these values, I want to use labels to store the large numbers in, but as 
>> I have to do it for a large number of maps (which are generated during 
>> simulations) I can't do it manually by using r.support interactively.
>>
>> Therefore my question: is there a way to either store the values in the 
>> grid cell itself instead of the category value or if not, how can I 
>> create these labels non-interactively?
> 
> The cats file format is simple enough that you could generate it from
> a script. See the cats files for the sample datasets (e.g. Spearfish)
> for examples.
> 
> Generating a cats file using the libgis functions is also quite
> straightforward e.g.:
> 
> 	const char *map_name = "outmap";
> 	const char title[] = "title string";
> 	const char *labels[NUM_CATS] = { ... };
> 	struct Categories cats;
> 
> 	G_init_cats(0, title, &cats);
> 
> 	for (i = 0; i < NUM_CATS; i++)
> 		G_set_cat(i, (char *) labels[i], &cats);
> 
> 	G_write_cats ((char *) map_name, &cats);
> 

Thanks - but as you suggested above, the DCELL solution appeals more to me.