||SVS - Stand Visualization System
|A product of the USDA Forest Service,
Pacific Northwest Research Station
The Stand Visualization System or SVS generates graphic
images depicting stand conditions represented by a list of individual stand
components, e.g., trees, shrubs, and down material
(example SVS image 67k). The images produced by SVS, while abstract,
provide a readily understood representation of stand conditions. Images
produced using SVS help communicate silvicultural treatments and
forest management alternatives to a variety of audiences.
SVS provides the following capabilities:
Display stand information represented by a list of individual plant and
log components in a realistic, although abstract, fashion
Display stand information in a manner that communicates the overall structural
diversity present within the stand
Differentiate between stand components using different plant forms, colors,
or other types of marking
Provide overhead, profile and perspective views of a stand
Allow the user to vary the parameters controlling all views
Allow users to define plant forms and colors based on species, plant type,
and plant position within the canopy
Provide tabular and graphical summaries of stand information before and
after a silvicultural treatment
Display information describing individual stand components as they are
selected by the user
Allow the user to design of silvicultural treatments by "marking" stand
components and specifying a treatment
SVS requires two primary types of data: a list of stand components
and plant form definitions. The stand component list describes the species,
size and location of each component in a stand. Plant form definitions
describe the appearance of each species and, optionally, the appearance
of individuals exhibiting different growth forms within a species.
The following parameters describe each stand component:
The MAKESVS utility, included with SVS, converts stand table input
consisting of species, dbh, height, and number of plants per unit area
into a list of individual components
||Crown radius 4
||Crown radius 1
||Crown ratio 4
||Crown ratio 1
||Crown radius 2
||Crown ratio 2
||Crown radius 3
||Crown ratio 3
Plant Form Definitions
Users define the appearance of each species represented in a component
list using a plant form definition. Form definitions describe the overall
growth form; geometry and number of branches or leaves; and color of the
stem, branches and foliage. SVS provides a "tree designer" to help
users develop form definitions for the species and growth forms in their
area. SVS uses the species identifier as the primary link between
the component list and the plant form definitions. However, two additional
parameters, tree class and crown class, can be used to distinguish individuals
within a species. Interpretation and use of these two parameters is under
the complete control of the user. SVS reserves the value of 99 for
the tree class and crown class to represent a "wild-card" value.
Plant Form Representations in SVS
SVS uses a tree designer dialog box (31k)
to allow users to easily modify the parameters that control the shape and
appearance of individual plants drawn by SVS. The tree designer uses four
windows to represent various views of a plant form. The upper left window
shows an overhead view of eight plants. The upper right window shows a
series of plants with decreasing crown ratios. The lower left window shows
a group of plants that exhibit a variety of size and shape characteristics.
The lower right window shows a single plant. The lower right window also
contains controls to establish the average crown ratio, crown radius, and
height for the plant type. The parameters in the lower right window affect
only the size and scaling of the plants as drawn in the tree designer.
When drawing plants, SVS uses information in the component list to size
individual plants. The controls on the right side of the screen modify
the parameters used to represent a particular plant form. The species,
tree class, and crown class for the plant form being modified are displayed
along the top of the screen. The buttons along the bottom of the screen
provide access to stored plant definition files and allow the user to add
new plant forms or modify existing plant forms.
Designing Silvicultural Treatments with SVS
SVS allows users to create stand treatments
by marking individual trees (56k) on either the perspective or overhead
displays. Users can mark eight "scenarios" or treatments. A "View only"
option displays parameters for selected trees but does not change the mark
status of the selected tree.
Computer System Requirements
The DOS version of SVS, available but no longer supported, is designed
for IBM-compatible personal computers running the MS-DOS operating system.
DOS SVS requires the following computer configuration:
SVS can utilize a standard VGA graphics adapter to display 16 colors. With
a VESA compatible graphics adapter, SVS displays 256 colors.
80386, 80486, or Pentium CPU
1 Mb RAM (4 Mb or more recommended)
Mouse or other pointing device
VESA compatible graphics adapter (VESA, in this case, does not refer to
VESA local bus. The graphics adapter should be compatible with the protocol
developed by the Video Electronics Standards Association...consult the
manual for your graphics adapter for further information.)
The Windows version of SVS operates on Windows 95, 98, and NT (3.5+).
WINSVS should run on any computer capable of running one of these operating
This page was last modified on Feb 24, 1999
If you have comments or need additional information, contact Robert J.
McGaughey at the Pacific Northwest Research Station (firstname.lastname@example.org