[GRASS-user] Trento3D screenshots redone

[Markus Neteler]

Hamish wrote:

>>- interpolate dem to highres (I used 2m pixels) with r.surf.rst
>>    
>>
>
>is this really needed? g.region res=2 & NVIZ will smooth (or do you see
>flat patches/aliasing grid then?).
>  
>

I see stairs - it always depends on how much higher resolution it takes.
Maybe also r.bilinear
does a sufficient good job (and it is fast).

...

>>>I understand one must have the 
>>>building data (how was *that* obtained?).
>>>      
>>>
>>The Trento municipality was going out and digitizing all builings.
>>Another option is to digitize building footprints from orthophoto
>>(v.digit) and assign a typical height to each building.
>>    
>>
>
>trick: You don't need actual height of buildings, just number of floors.
>  
>
... which I don't have (but would like to have...)

>(how you did Trento version 1 Markus?)
>  
>
There was an odd values in the table which I misused. Now, having a
different
data set, I have the measured height.

>Interns can do orthophoto tracing work :)  .. LIDAR ..
>  
>

Better take stereo photo and "e-photo" software which apparently
recently learned
to extract DEM from stereo images.

BTW: I did it again, now we have buildings colored by their usage (sorry
for the odd
colors):
 http://grass.itc.it/grass61/screenshots/index.php

The procedure:
- extract new maps per usage type from original 2D map (v.extract)
- extrude each to 3D (v.extrude, a shell "for" loop is convenient)
- load all maps into NVIZ
- go to color editor for vector lines and change color (here a random
color button
  would be cool)

Cheers

 Markus