[GRASS-user] r.category value range

Martin Album Ytre-Eide Martin.Album.Ytre-Eide at nrpa.no
Thu Feb 5 02:12:17 PST 2015


Hey, thanks!

r.recode worked for me. As mentioned r.category clames it can do this, and in different cases - it might be more usefull to work with labels. I was trying to add labels and then do a "r.mapcalc expression="snow_type= @lwc_2014_05_15" " in order to use the labels as values. But r.recode did this in one go, so that was better. But if one was to use the labels in a label instead of the values - it would be good if the r.category worked as intended. I think I have done that before, so maybe label range (with r.category) works with d.legend? - did you try this Moritz?

Martin


________________________________________
Fra: grass-user-bounces at lists.osgeo.org [grass-user-bounces at lists.osgeo.org] på vegne av Moritz Lennert [mlennert at club.worldonline.be]
Sendt: 4. februar 2015 16:55
Til: Markus Metz
Kopi: grass-user at lists.osgeo.org
Emne: Re: [GRASS-user] r.category value range

On 04/02/15 15:51, Moritz Lennert wrote:
> On 04/02/15 15:45, Moritz Lennert wrote:
>> On 04/02/15 15:23, Markus Metz wrote:
>>> On Wed, Feb 4, 2015 at 1:14 PM, Moritz Lennert
>>> <mlennert at club.worldonline.be> wrote:
>>>> On 04/02/15 11:48, Martin Album Ytre-Eide wrote:
>>>>>
>>>>> Hello!
>>>>>
>>>>> I trying to set a label  for a range of values in  a raster.
>>>>>
>>>>> I am using r.category (grass 7.0)
>>>>>
>>>>> "r.category map=lwc_2014 separator=':' rules=lwc.rules"
>>>>>
>>>>> My lwc.rules looks like this:
>>>>>
>>>>> 0:30:0.9
>>>>> 31:90:0.7
>>>>> 91:252:0.5
>>>>>
>>>>> so, r.category does not seem to read my range, but in stead gives me
>>>>> labels for value 31 (label=90:0.7) and value 91 (label=252:0.5)
>>>>>
>>>>> Any clues to what I am doing wrong ? or is r.category not working as
>>>>> intended?
>>>>
>>>>
>>>> You should use r.recode, not r.category.
>>>
>>> According to the manual, r.category should work with these rules.
>>
>> You're right. Sorry, I wrote to fast.
>>
>> Actually the manual also says concerning the example: "The format is
>> given as follows (when separator is set to colon)". So, AFAIU, you have
>> to set the separator parameter to whatever separator you use in the rules.
>>
>
> Sorry, I really should take the time before I write. I can reproduce the
> issue actually:
>
>
> g.copy raster=geology_30m,mygeol
> r.category mygeol rules=- separator=':' <<EOF
> 217:270:1
> 405:862:2
> 910:948:3
> EOF
> r.category mygeol
> 217   270:1
> 262
> 270
> 405   862:2
> 583
> 720
> 766
> 862
> 910   948:3
> 921
> 945
> 946
> 948
>
> So, yes, there seems to be a bug in r.category. Please file a ticket.

Looking at the code, I actually think that r.category works well in
terms of setting the label for the range. At least the cats file reads:

# 948 categories


0.00 0.00 0.00 0.00
217:270:1
405:862:2
910:948:3

which looks correct to me.

However, it does not know how to display it in a decent manner. The same
goes for d.legend. Or r.what. IIUC, modules that read cat values just
don't seem to have been foreseen for this case.

So, for the OP, I would go back to my original answer to suggest using
r.recode.

And maybe someone who understands the code better than me can clarify
how GRASS is supposed to actually use such range labels ?

Moritz
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