The Vegetation Transition Magnitude (VTM) product represents the relative magnitude of change applied to a pixel during the LANDFIRE (LF) vegetation update process. This product provides information regarding disturbance type and the resulting impact on vegetation life-form or tree canopy cover through 2014.
The mapping process integrates Annual Disturbance products. The effect of these disturbances on the vegetation are modeled or predicted using tables linking pre-disturbance existing vegetation type, height, and cover and possible disturbance types and severities with post-disturbance existing vegetation type, height, and cover. Forested vegetation tables are informed by computer simulations in the Forest Vegetation Simulator (FVS) while non-forest vegetation is informed by a series of simple rule-sets generated for each map zone. The tables spatially link vegetation and disturbance to assign existing vegetation, height, and cover. A code is assigned to unique combinations of disturbance type and change magnitude, which is expressed either in a change of vegetation life-form or a change in tree cover.
The comma separated value (CSV) file used for the raster attribute table is included in the LF product download in database file (DBF) format.
(Why is the CSV important?)