[GRASS5] growing trees with v.trees3d and save a 2D image

GRASS GIS GRASS GIS developer
1

Hi all,
a student would like to grow trees iteratively and compare the outputs
with an aerial photo, while changing trees parameters from one
iteration to the other.

We finally agreed that v.trees3d would do well for a good start at that job.
We identified that we needed an elevation base map (OK), and a tree
point location map (OK).

When i got to check GRASS6.1cvs, there is no g3.* commands, so i got
confused on how to setup the 3D study area. I checked in 6.0.2RC4, and
also no sign of g3* commands, maybe wrong compilation? Or is there
another way? Any tutorial online?

Then once the study area is setup, i would like to know if there is a
command line possibility to have a png (or any image format) of the
study area from a normal angle to the scene. We mean to ask another
program to control GRASS to do this again and again, until it finds
the proper combination of parameters to describe the trees in the
aerial photo.

Any help, information, orientation would be welcome!
Yann

2

Then once the study area is setup, i would like to know if there is a
command line possibility to have a png (or any image format) of the
study area from a normal angle to the scene. We mean to ask another
program to control GRASS to do this again and again, until it finds
the proper combination of parameters to describe the trees in the
aerial photo.

Set the view in NVIZ, then File->Save State ..

Then make a script (see the scripting menu) to automatically trigger the
File->Save image as->PPM. Convert that to PNG with pnmtopng from Netpbm.

or just modify the nviz2.2_script Tcl file to auto call that function
with a known filename after starting grass with "nviz state=file.nviz".

It's definitely possible, but you will have to get your hands a little
dirty.

Hamish