[GRASSLIST:6314] Re: filling nulls in integer raster

[Dylan Beaudette]

Maciek,

interesting idea,

I tried using r.neighborhood as well, and it seemed to work ok.

however, i have since discovered that for this particular raster (as  
classified slope map of very complex terrain) it was simpler to  
generalize the slope map via r.param.scale. since we are mapping at a  
rather coarse scale, this method actually captures the larger terrain  
features, while masking out the smaller ones..!

i was able to vectorize, and then clean with tool=rmarea to get rid of  
any remaining small areas

thanks!

--
Dylan Beaudette
Soils and Biogeochemistry Graduate Group
University of California at Davis
530.754.7341


On Apr 1, 2005, at 1:07 PM, Maciek Sieczka wrote:

> what do you think of the neighborhood modifier:
>
> 1 change the null value to eg. 0
>
> 2 r.mapcalc  
> 'map_filled=if(map==0,mode(map[-1,-1],map[-1,0],map[ 
> -1,1],map[0,1],map[1,1],map[1,0],map[1,-1],map[0,-1]),map)'
>
> 3 repeat until no zeros (may be recognized with "r.info -r  
> map_filled") if needed
>
> or maybe mask the non-null areas, r.grow the mask a few pixels,  
> r.neighbors, g.remove MASK, r.patch?
>
> Maciek
>
> ----- Original Message ----- From: "Dylan Beaudette"  
> <dylan at iici.no-ip.org>
> To: <GRASSLIST at baylor.edu>
> Sent: Friday, April 01, 2005 9:55 PM
> Subject: [GRASSLIST:6310] filling nulls in integer raster
>
>
>> Greetings,
>>
>> i have a raster image that i am hoping to vectorize after a bit of
>> generalization with r.reclass.area... however, r.reclass.area leaves  
>> nulls
>> in
>> the middle of larger areas of equal value:
>>
>> http://169.237.35.250/~dylan/temp/holes.png
>>
>> i have tried to fill these holes, with r.fillnulls (via RST  
>> interpolation)
>> with:
>> r.fillnulls in=asp.large out=asp.final smooth=.01 tension=100
>>
>> and the result looks something like this:
>>
>> http://169.237.35.250/~dylan/temp/fewer_holes.png
>>
>>
>> ...however, is there anyway to get rid of all the nulls, replacing  
>> them
>> with
>> the value that is surrounding them?
>>
>> thanks in advance
>>
>>
>> -- 
>> Dylan Beaudette
>> Soils and Biogeochemistry Graduate Group
>> University of California at Davis
>> 530.754.7341
>>
>>
>
>
>