Smathermather's Weblog

Remote Sensing, GIS, Ecology, and Oddball Techniques

Archive for October, 2008

Povray Viewshed with Trees (finally) (cont.)

Posted by smathermather on October 9, 2008

Ok, your average terrain-only based viewshed (view is from a road to the southeast, viewshed is in cyan):

Note that based on these estimates, we should be able to see most of the valley walls from this little slice of road.  I don’t buy that.  That section of road is pretty closed in with trees.  Let’s add them:

As you may see, just a little cyan in the southeast mostly along the road.  Here’s where you can see the trees occluding our view of the viewshed a bit.  But, it’s a first good stab, even with such boring results… .  I’ll have to get that section of road in here that peeks out over the gorge.  But first, I’ll have to see if I can get tree stem locations from the lidar, so we can trade up for some veracity in our analysis.  Stay tuned.

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Povray Viewshed with Trees (finally)

Posted by smathermather on October 8, 2008

Povray Viewshed with Trees: still some tweaking to do, especially tweaking that represents the real location and size of trees on the landscape, but if we cannot yet have veracity, best to have some verisimilitude.  Also, long term, it’d be nice if the light sources would be effected by the trees, but not the camera.  The trees occlude the ability of the camera to see what the full viewshed is.  Not clear what I mean?  Give me a few days, something nagging the back of my brain says the solution is trivial.  In the mean time, here’s the code:

Now for the include files: (can you tell I’m not using version control):

Images to come of the output.  It is rendering as we speak.  I didn’t like the Povray 3.7 beta versions I ran at work on a much faster computer, so now I’m waiting for it to finish on my wife’s laptop… .

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Povray Landscape with Trees

Posted by smathermather on October 4, 2008

Just a short teaser post until I remember to bring the code home with me, but I’ve placed trees within the bounds of a canopy layer determined from some county LiDAR dataset.  The tree locations, heights, and rotation are set using pseudo-random numbers, which looks a lot better than a monoculture of the same tree.  Eventually, estimating stem locations and canopy heights to do this would be preferable, but one step at a time… .  We’ll first look for a reasonable result, and follow with an accurate one.  For now I get a pretty realistic canopy over a gorge area for a creek, so below are the first, middle-ish, and last frames in an animation I did of that canopy.

Close in:

rendering partway up…

(Check out the creek running through the gorge)

(Check out the creek running through the gorge)

And the final frame:

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