On 07/05/12 16:36, Daniel Lee wrote:
Hi Tanya,
I would use r.distance rather than r.grow.distance and then reclassify
the results to include only areas with <=1108 m distance - that should
be a lot easier.
I don't think r.distance gives what you want, however r.grow.distance
should be exactly your tool:
As a starting point you need a raster map with all pixels in the orchard
non-null and all other pixels null Let's call that raster map
'orchard'. Then you can do the following:
r.grow.distance input=orchard distance=distance_map
Then, if you only want to see the distance from the orchard to 1108m,
then you can use r.mapcalc:
r.mapcalc "final_distance_map=if(distance_map>1108, null(), distance_map)"
All this keeping in mind that I don't understand what you mean by "I
recognize this tool does not allow a distance to be included".
If this means that you also want to measure a distance _within_ the
orchard, then instead of using a raster map of the orchard, use as input
to r.grow.distance a raster map with only the center pixel of the
orchard non-null.
Moritz
2012/5/7 Tanya Dyck <[email protected] <mailto:[email protected]>>
Hello,
I am trying to run the grow.distance command to create a raster that
displays the euclidean distance from an 'orchard' outward to 1108m.
I am not trying to measure the distance between 2 non-null
features, but simply wish to have the euclidean distance extend out
from the orchard to 1108m. I recognize this tool does not allow a
distance to be included so I created a buffer around my orchard
(1108m) and intended to run grow.distance on that, however it
outputs the distance as if it includes the full raster extent (so I
have an output raster of 1108m that is all yellow as opposed to a
range of values displaying varying distances) and not limited to my
buffer. I want it to assume the buffer extent is the raster extent,
so to speak. Is there another way to do this?
Any ideas would be much appreciated.
Best,
Tanya
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