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# brainteaser viewshed wind turbines - the more you see the worse it gets...

Question asked by geonetadmin on Aug 2, 2013
Latest reply on Aug 7, 2013 by csny490
Original User: firefry82

working with arcgis 10.1 Sp1

Hi everybody,
I have a little brainteaser for you: I am trying to make a visibility analysis of wind turbines.  But instead of the simple viewshed thing,  I am trying to include stuff like partial visibility and multiple visibilities. The latter one is driving me insane and I hope some of you guys (or girls of course) maybe have an idea how to approach this.
I have zones around each single turbine, which indicate the level of visual distress in relation to the distance.
[ATTACH=CONFIG]26444[/ATTACH]
I can now merge them to a big viewshed which works fine.

To include the multiple visibilities I need to consider the folowing idea from "Paul et al. 2004"

[ATTACH=CONFIG]26442[/ATTACH]
Paul et al 2004 & ECOGIS
Even though this is for tension towers I think it is about the same for wind turbines. It says that the visibility  increases when more when multiple turbines are visible. So he set up a factor which is 1 for the closest turbine, 1/2 for the second closest,  1/3 for the third closest and so on (1/i). Now how do I find out which turbine is closest to each cell from my raster? and then how do I get a hold of the zone-id?

This is the idea sketch:

[ATTACH=CONFIG]26447[/ATTACH]

What I tried so far:
1) converted viewsheds to polygones, made union analysis to try to intersect each one with the other to find overlapping areas. Then could go through each row and find the biggest zone-id which would be taken in account by the factor 1, the second biggest zone-id with 1/2 and so on. --> failed because union analysis can'T handle the data load

2) tried intersect the the polygon-viewsheds without  the union,  but then only a small part in which they ALL intersect is produced. I the searched for a intersect method that maybe finds and visualizes all the intersections from the overlaps...but I didn't find anything

3) tried to work it out with the raster calculator, but then I wouldn't know how to tell him that he should only take the zone-value when it is the closest to the cell...

I just can't get my head around it...

I am open for any ideas, phyton-scripts, ...whatever...