NAME¶
wxGUI.Nviz
DESCRIPTION¶
Note:
wxGUI 3D view mode is currently under development. It's provided
as an experimental prototype.
wxNviz is a
wxGUI 3D view mode which allows users to
realistically render multiple
surfaces (raster data) in a 3D space,
optionally using thematic coloring, draping 2D
vector data over the
surfaces, displaying 3D vector data in the space, and visualization of
volume data (3D raster data).
To start the wxGUI 3D view mode, choose '3D view' from the map toolbar.
wxNviz is emphasized on the ease and speed of viewer positioning and provided
flexibility for using a wide range of data. A low resolution surface or wire
grid (optional) provides real-time viewer positioning capabilities. Coarse and
fine resolution controls allow the user to further refine drawing speed and
detail as needed. Continuous scaling of elevation provides the ability to use
various data types for the vertical dimension.
For each session of wxNviz, you might want the same set of 2D/3D raster and
vector data, view parameters, or other attributes. For consistency between
sessions, you can store this information in the GRASS
workspace file
(gxw). Workspace contains information to restore "state" of the
system in 2D and if wxNviz is enabled also in the 3D display mode.
- Switch to view page
-
Switch 3D Layer Manager Toolbox's page to the view control page.
- Switch to surface page
-
Switch 3D Layer Manager Toolbox's page to the surface control page
(data properties).
- Switch to vector page
-
Switch 3D Layer Manager Toolbox's page to the vector control page
(data properties).
- Switch to volume page
-
Switch 3D Layer Manager Toolbox's page to the volume control page
(data properties).
- Switch to light page
-
Switch 3D Layer Manager Toolbox's page to the light control page
(appearance).
- Switch to fringe page
-
Switch 3D Layer Manager Toolbox's page to the fringe control page
(appearance).
- Show 3D view mode settings
-
Show dialog with settings for wxGUI 3D view mode. The user settings can be
stored in wxGUI settings file.
- Show help
-
Show this help.
- Quit
-
Quit 3D view mode and switch map display to the 2D view mode.
The 3D view toolbox is integrated in the Layer Manager. The toolbox has several
tabs:
- View for view controling,
- Data for data properties,
- Appearance for appearance settings (lighting,
fringes, ...).
View¶
You can use this panel to set the
position, direction, and
perspective of the view. The position box shows a puck with a direction
line pointing to the center. The direction line indicates the look direction
(azimuth). You click and drag the puck to change the current eye position. The
box annotations are North, South, East, and West. You can also set exact
position using
Look at choice control.
You can adjust the viewer's height above the scene, angle of view or twist value
to rotate the scene about the horizontal axis. An angle of 0 is flat. The
scene rotates between -90 and 90 degrees.
You can also adjusts the vertical exaggeration of the surface. As an example, if
the easting and northing are in meters and the elevation in feet, a vertical
exaggeration of 0.305 would produce a true (unexaggerated) surface.
Reset returns all current settings to their default values.
Data properties - Surface¶
Each active raster map layer from the current layer tree is displayed as surface
in the 3D space. Separate raster data or constants can be used for various
attributes of the surface:
- topography - raster map or constant values used as
elevation (z values) for the current surface.
- color - raster map or constant color to drape over
the current surface. This option is useful for draping imagery such as
aerial photography over a DEM.
- mask - raster map that controls the areas displayed
from the current surface.
- transparency - raster map or constant value that
controls the transparency of the current surface. The default is
completely opaque. Range from 0 (opaque) to 255 (transparent).
- shininess - raster map or constant value that
controls the shininess (reflectivity) of the current surface. Range from 0
to 255.
- emission - raster map or constant value that
controls the light emitted from the current surface. Range from 0 to
255.
This panel controls how loaded surfaces are drawn. The top half of the panel has
options to set, unset or modify attributes of the current surface. The bottom
half has drawing style options, masking or changing surface position in the
space.
Surface can be drawn as a wire mesh or using filled polygons (most realistic).
You can set draw
mode to
coarse (fast display mode),
fine
(draws surface as filled polygons with fine resolution) or
both (which
combines coarse and fine mode). Additionally set coarse
style to
wire to draw the surface as wire mesh (you can also choose color of the
wire) or
surface to draw the surface using coarse resolution filled
polygons. This is a low resolution version of the polygon surface style. E.g.
surface is drawn as a wire mesh if you set
mode to
coarse and
style to
wire. Note that it differs from the mesh drawn in fast
display mode because hidden lines are not drawn. To draw the surface using
filled polygons, but with wire mesh draped over it, choose
mode
both and
style wire. Beside mode and style you can also
choose style of
shading used for the surface.
Gouraud style
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.
To set given draw settings for all loaded surfaces press button "All".
Data properties - Vector¶
2D vector data can be draped on the selected surfaces with various markers to
represent point data; you can use attribute of vector features to determine
size, color, shape of glyph. 3D vector data including volumes (closed group of
faces with one kernel inside) is also supported. This panel controls how
loaded 2D or 3D vector data are drawn.
You can define the width (in pixels) of the line features, the color used for
lines or point markers.
If vector map is 2D you can display vector features as flat at a specified
elevation or drape it over a surface(s) at a specified height. Use the height
control to set the flat elevation or the drape height above the surface(s).
For display purposes, it is better to set the height slightly above the surface.
If the height is set at zero, portions of the vector may disappear into the
surface(s).
For 2D/3D vector points you can also set the size of the markers and the width
(in pixels) of the line used to draw the point markers (only applies to
wire-frame markers). Currently are implemented these markers:
- x sets the current points markers to a 2D
"X",
- sphere - solid 3D sphere,
- diamond - solid 3D diamond,
- cube - solid 3D cube,
- box - hollow 3D cube,
- gyroscope - hollow 3D sphere,
- asterisk - 3D line-star.
Data properties - Volume¶
Volumes can be displayed either as isosurfaces or slices. Various attributes of
the isosurface can be defined, similarly to surface attributes:
- level - reference isosurface level (height in map
units).
- color - raster map or constant color to drape over
the current volume.
- mask - raster map that controls the areas displayed
from the current volume.
- transparency - raster map or constant value that
controls the transparency of the current volume. The default is completely
opaque. Range from 0 (opaque) to 255 (transparent).
- shininess - raster map or constant value that
controls the shininess (reflectivity) of the current volume. Range from 0
to 255.
- emission - raster map or constant value that
controls the light emitted from the current volume. Range from 0 to
255.
This panel controls how loaded volumes are drawn. Volume can be drawn in two
different modes:
isosurface or
slice. The top part of the panel
has drawing style options. The middle part has controls to add, delete, move
up/down selected isosurface or slices. The bottom part has options to set,
unset or modify attributes of the current isosurface or slice.
Similarly to surface panel you can define draw
shading -
gouraud
(draws the volumes with a smooth shading to blend individual cell colors
together) and
flat (draws the volumes with flat shading with one color
for every two cells. The volume appears faceted). As mentioned above currently
are supported two visualization modes:
- isosurface - the levels of values for drawing the
volume(s) as isosurfaces,
- and slice - the levels of values for drawing the
volume as cross-sections.
Settings¶
This panel has controls which allows user to set default surface, vector and
volume data attributes. You can also modify default view parameters, or to set
the background color of the Map Display Window (the default color is white).
To be implement¶
- Improve intuitive navigation (mouse, fly mode)
- Animation capabilities
- Arbitrary cutting planes
- Labels, decoration, etc.
- Scripting capabilities
- Better workspace support (view settings, lighting)
- Surface - mask by zero/elevation, more interactive
positioning
- Vector points - implement display mode flat/surface for 2D
points
- Volume - slice draw mode
Please note that wxNviz is under active development and distributed as
"Experimental Prototype".
SEE ALSO¶
wxGUI
Other wxGUI components:
Vector Digitizer
Attribute Table Manager
Graphical Modeler
Manage Ground Control Points
Cartographic Composer
See also wiki page.
Command-line module
m.nviz.image.
Original TCL/TK-based Nviz.
AUTHORS¶
Martin Landa, Google Summer of Code 2008 (mentor: Michael Barton) and Google
Summer of Code 2010 (mentor: Helena Mitasova)
$Date: 2011-10-14 19:44:26 +0200 (Fri, 14 Oct 2011) $
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