Help with 3D: Difference between revisions

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== Raster 3D (voxels) ==
== Raster 3D (voxels) ==


intro
Support for 3D rasters (voxels) is relatively new in GRASS and is primarily handled by [http://grass.itc.it/grass63/manuals/html63_user/raster3D.html the r3.* modules].
A 3D raster can be thought of as a stack of 2D raster maps forming a 3D cube of data cells.


* r3.* help pages
==== Region settings ====
Region settings are handled by the [http://grass.itc.it/grass63/manuals/html63_user/g.region.html g.region] module.
Special 3D raster settings for ''g.region'' include:
-3 flag:  Prints 3D settings
      t  Value for the top edge
      b  Value for the bottom edge


===== Example =====
    res3  3D grid resolution (north-south, east-west and top-bottom)
  tbres  Top-bottom grid resolution 3D


vox50 script
and
  rast3d  Set region to match this 3D raster map (both 2D and 3D values)
(??)  3dview  Set region to match this 3dview file
 
* [http://grass.itc.it/grass63/manuals/html63_user/raster3dintro.html An introdution to 3D rasters]
 
 
===== Examples =====
 
* rain
 
* vox50 script


== Vector 3D point data ==
== Vector 3D point data ==

Revision as of 05:45, 16 October 2006

Raster 2.5D

This is the "typical" case, and most GRASS r.* modules work in this mode. The GIS layer is defined by north,south,east,west and the raster map's cell values represent the elevation.

Snippet from the Wikipedia definition: "The idea is that the program's canvas represents a normal 2D painting surface, but that the data structure that holds the pixel information is also able to store information regarding z-index (depth) as well as other information such as material settings, specularity, etc. With this data it is thus possible to simulate lighting, shadows, and so on."

Example

(spearfish dataset)

g.region rast=elevation.10m
nviz elev=elevation.10m

Raster 3D (voxels)

Support for 3D rasters (voxels) is relatively new in GRASS and is primarily handled by the r3.* modules. A 3D raster can be thought of as a stack of 2D raster maps forming a 3D cube of data cells.

Region settings

Region settings are handled by the g.region module. Special 3D raster settings for g.region include:

-3 flag:  Prints 3D settings
      t   Value for the top edge
      b   Value for the bottom edge
   res3   3D grid resolution (north-south, east-west and top-bottom)
  tbres   Top-bottom grid resolution 3D

and

 rast3d   Set region to match this 3D raster map (both 2D and 3D values)

(??) 3dview Set region to match this 3dview file


Examples
  • rain
  • vox50 script

Vector 3D point data

  • v.in.ascii -z
  • r.in.xyz
Example

Vector 3D polygons

intro screenshot of trento

  • v.in.ascii -z


Example

pyramid: the following is an example of 3D vector surfaces in GRASS standard ascii format. load with v.in.ascii.

# 3D Pyramid in GRASS:  (kernel currently unused?)
#  v.in.ascii in=pyramid.vasc out=pyramid_3d format=standard -nz
#  g.region n=150 s=-50 w=-50 e=150 res=10
#  r.mapcalc one=1
#  nviz elev=one vect=pyramid_3d
#
#  tip: in nviz try setting the raster surface transparency to 50%
#
F 5
 0 0 10
 0 100 10
 100 100 10
 100 0 10
 0 0 10
F 4
 0 0 10
 50 50 80
 100 0 10
 0 0 10
F 4
 0 100 10
 50 50 80
 0 0 10
 0 100 10
F 4
 100 100 10
 50 50 80
 0 100 10
 100 100 10
F 4
 100 0 10
 50 50 80
 100 100 10
 100 0 10
K 1 1
 40 50 40
 1 1


Visualization Tools

  • NVIZ
  • output to VTK
  • output to POVray
  • output to V5D