GRASS Tutorial for nviz

# NVIZ Reference Manual

CONTENTS

## Surface Panel

The Surface panel controls how loaded surfaces are drawn. The top half of the panel has drawing style options. The bottom half has options to add, delete, select, and change attributes of the current surface.

### OPTIONS

Surface Style
  Sets the style for drawing the final surface.
  Wire
    Draws the surface as a wire mesh. This differs from the mesh drawn in fast display mode (see Grid Style) because hidden lines are not drawn.
  Polygon
    Draws the surface using filled polygons (most realistic).
  Wire/Poly
    Draws the surface using filled polygons, but with wire mesh draped over it.
Grid Style
  Sets the style for drawing the fast display mode surface.
  Wire
    Draws the grid (fast display mode) as a wire mesh.
  Coarse Surface
    Draws the grid (fast display mode) using coarse resolution filled polygons. This is a low resolution version of the Polygon surface style. The decimation factor is set from the Grid Resolution (see above).
Shading
  Sets the style of shading used for the surface.
  Gouraud
    Draws the surfaces with a smooth shading to blend individual cell colors together.
  Flat
    Draws the surfaces with flat shading with one color for every two cells. The surface appears faceted.
Grid Resolution
  Sets the resolution of the coarse surface (default) or wire mesh. To switch between coarse surface and wire mesh select Grid Style (see below).
Polygon Resolution
  Sets the resolution of the final surface. The resolution is a function of the current GRASS region. For example, a resolution of 1 draws every raster cell in the current region.
Current Surface Only
  Applies resolution changes to the currently selected surface only.
All Surfaces
  Applies resolution changes to all loaded surfaces.
Current
  Shows the name(s) of all the loaded surfaces. You can use this menu to select a new current surface.
New
  Loads a new surface or surface constant.
Delete
  Deletes (unload) the current surface.
Surface Attribute
  You can use this menu to control the attributes of the current surface.
  topography
    Loads a new raster or constant value to use as elevation (z values) for the current surface.
  color
    Loads a raster or constant color to drape over the current surface. This option is useful for draping imagery such as aerial photography over a DEM.
  mask
    Loads a raster or constant that controls the areas displayed from the current surface.
  transparency
    Loads a raster or constant that controls the transparency of the current surface. The default is completely opaque.
  shininess
    Loads a raster or constant that controls the shininess (reflectivity) of the current surface.
  emission
    Loads a raster or constant that controls the light emitted from the current surface.
Wire Color
  Sets a wire color for the current surface. The color can be a constant or set from the current surface color.
Position
  Changes the x, y, and z position of the current surface.
Mask Zeros by
  Masks the current surface where elevation or color values are equal to zero.
  Elevation
    Masks elevation values equal to zero. The second No Zeros masks color values equal to zero.
  Color
    Masks color values equal to zero.
Draw Current
  Draws the current surface.
Close
  Closes the Surface panel.