[GRASSLIST:6311] Re: filling nulls in integer raster

[Maciek Sieczka]

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
>
>