NAME
Bars
DESCRIPTION
This module creates 3-D bars to represent the data values of a 2-D
lattice. The lengths of the bars are directly proportional to the absolute
values of the data. Bars is similar to the Graph3D module, but it is not
limited to uniform coordinates plus it provides a number of other
options. Among these include the ability to generate the bars only for a
selected data range with optional special value removal, map
projections, data thresholding, scaling, offsetting, and different types
of bars (blocks, cylinders, or cones) with type specific parameters.
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NOTE: This module contains some projection code borrowed from
the Projector module written by James Phillips at the Minnesota
Supercomputer Institute and Department of Geology and Geophysics,
University of Minnesota.
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INPUTS
Input -- Lattice
(2-D, 1-vector, float).
This is the lattice used for generating the bars.
Colormap -- Lattice
(1-D, 4-vector, float, uniform).
This is the lattice used to color the bars.
WIDGETS
Height Scale -- Slider
This is a scaling factor to be applied to the data values for adjusting the
heights of the bars.
Width Scale -- Slider
This is a scaling factor to be applied to the widths of the bars for
adjusting the spacing between them.
Z Offset -- Slider
This is an offset value to be applied to starting position of the bars for
displacing them vertically.
Set Threshold? -- Option Menu
This determines whether the "Data Threshold" value is used to limit the
number of bars created based on their data values.
Data Threshold -- Text
This is a threshold value for the data to be compared against. If "Set
Threshold?" is "Yes" then the bars with data values less than or equal
to this threshold will be collapsed into their bottom or top rectangles
based on the "Length Type" setting.
Range Type -- Option Menu
This toggles between generating bars for all the data values of the
lattice ("Full") or only for the range specified by the "Range Start" and
"Range End" values ("Selected"). If "Full" is selected then the range
widgets will be disabled.
Range Start -- Dial
This is the lower bound of the selected range of data values for which
to generate bars.
Range End -- Dial
This is the upper bound of the selected range of data values for which
to generate bars.
Projection -- Option Menu
This is the current map projection. The input lattice should have
geographic coordinates for the projection to be meaningful. Bars
provides the same projections as the Projector module (Cartesian,
Mercator Cylindrical, Lambert Cylindrical, Gnomonic Azimuthal,
Stereographic Azimuthal, Orthonormal Azimuthal, Postel Azimuthal,
Lambert Azimuthal, Lambert Conical, Albers Conical, Cassini-Soldner,
Bonne Connical, Werner, Sanson-Flamsteed, and Globe). See
Projector's help file for more information about these projections.
Projection Radius -- Text
If a projection is selected then this value is used as the radius to
provide proper scaling of the longitudes and latitudes.
Base Lon. -- Slider
This is the base longitude for the center of the map projection. It is not
used for the "Globe" projection.
Base Lat. -- Slider
This is the base latitude for the center of the map projection. It is not
used for the "Globe" projection.
1st St. Par. -- Slider
This is the 1st standard parallel used by the "Lambert Conical" and
"Albers Conical" projections. It indicates the intersection of a cone
with the projection.
2nd St. Par. -- Slider
This is the 2nd standard parallel used by the "Lambert Conical" and
"Albers Conical" projections. It indicates the intersection of a cone
with the projection.
Length Type -- Option Menu
This determines the way the lengths of the bars are extended. The
"Regular Base" option starts the base of a bar at the coordinates of its
cell location then if its data value is positive, the bar extends upward
and if it's negative, the bar extends downward. The length of an
extension is determined by the data value and the "Height Scale". The
"Minimum Base" option uses the same ending locations of the bars as
"Regular Base", but they are all then extended further downward to the
lengths specified by the minimum data values (after scaling).
Bar Type -- Option Menu
This determines the geometric object used to represent the "bars". The
default is ordinary rectangular blocks, but they can also be cylinders or
cones.
Dimension -- Radio Box
This selects how the bar geometry is to be drawn (points, lines, or
shaded polygons). Lowering the dimension will speed up rendering for
better interactive manipulation.
Line Width -- Slider
When the bars are drawn as line segments, this sets their pixel width.
Complexity -- Slider
This is the complexity to be applied to the geometry when the bars are
drawn as cylinders or cones. The larger the complexity, the more
polygons are used to create these objects. The range is from 0.0 to 1.0.
Larger complexity values can SIGNIFICANTLY reduce rendering speed
when there are many objects.
Remove Special? -- Option Menu
This determines whether bars are created for the data values that match
the "Special Value".
Special Value -- Text
This is data value that should be treated as "special" when "Remove
Special?" is set to "Yes".
OUTPUTS
Output -- Geometry
This is the geometry for the bars.
KNOWN PROBLEMS
There are no known bugs.
SEE ALSO
Graph3D, Projector
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Hans Vahlenkamp (Hans.Vahlenkamp@noaa.gov)
Geophysical Fluid Dynamics Laboratory / NOAA
Princeton University Forrestal Campus
http://www.gfdl.noaa.gov
