Nathaniel Iwuchukwu wrote:
I figured it out.
here are my new output. though the lines are scattered. can it be
improved?
Again, Nathaniel, keep the discussion on the list, both to get more
responses, and for future generations.
The next step you might try is using the v.clean command on this vector
to remove very small lines. It has a tool, rmdangle to get rid of all
the small X's around the actual roads. You will have to experiment with
the "thresh" parameter to get it right.
Regards,
Micha
On Fri, Apr 2, 2010 at 5:41 AM, Nathaniel Iwuchukwu
<[email protected] <mailto:[email protected]>> wrote:
Thanks Micha,
I was thinking of running the r.mapcalc command but not sure of
the exact argument to use.
is there a command i can run to show me the values of the colors
on the map?
Thanks
Nathaniel
On Fri, Apr 2, 2010 at 8:27 AM, Micha Silver <[email protected]
<mailto:[email protected]>> wrote:
Nathaniel Iwuchukwu wrote:
here are the image results of my works. am trying to
upload it on my page
If you do upload the images, post also to the list.
It looks like all the areas that are *not* roads are also
being classified. Everywhere that appears purple in you
classification image needs to be set to null. You do this with:
r.null <classified_raster> setnull=<the value which displays
purple>
You want to be left with a raster with values *only* where
there are roads. Everything else should be null. Then go ahead
and run:
r.thin and r.to.vect <classified_raster_thin> feature=line
out=roads
Cheers,
Micha
2010/4/1 Micha Silver <[email protected]
<mailto:[email protected]> <mailto:[email protected]
<mailto:[email protected]>>>
On 04/01/2010 02:52 PM, Nathaniel Iwuchukwu wrote:
i created 11 polygons from different portions of
the road.
So if I understand correctly, the procedure is working,
but you're
not getting the results you'd expect?
Maybe you could supply to the grass-users list some
URL's of
images of what the satellite rasters look like, with
your training
polygons, and the resulting roads. Then perhaps someone
will be
able to suggest how to get more complete results.
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Micha Silver
Arava Development Co. +972-52-3665918
http://www.surfaces.co.il
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