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:

Data Requirements

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:

Species code  End diameter Crown radius 4
Plant class  Crown radius 1 Crown ratio 4
Crown class  Crown ratio 1 Expansion factor
Plant status  Crown radius 2 Marking status
Diameter  Crown ratio 2 X
Height Crown radius 3 Y
Felling angle  Crown ratio 3 Elevation
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

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.

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 systems.

Obtaining the Software

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 ( ).