Model Notifications

Incorrect Relative Age Setting in VDDT: The vegetation models for some eastern zones had an incorrect setting for relative age in the VDDT database.

Background & Advice:

Relative age was not set correctly in the following eastern zones when they were first made available for download from www.landfire.gov: 25, 26, 27, 29, 30, 33, 34, 37, 44, 45, 55, 56, 58, and 98. Relative age, according to LANDFIRE (LF) modeling rules, should be set to the inverse of the end age of the class (for example, if the class end age is 10 and relative age is used, it should be set to -10). In the aforementioned zones, relative age was set to the class end age rather than the inverse of the class end age. In some cases, an incorrect relative age setting could change the model results. The LF team has corrected the relative age issue and redelivered corrected files. For zone 25 a new version of the model description document was released to correct inaccurate descriptive information related to this issue. For all other zones, only the VDDT database was changed. The error in the relative age setting did not affect any of the mapped products. Customers are advised to delete any local version 1 databases (that is, those that have "v1" in the file name) they may have downloaded and replace them with the version 2 databases (those that have "v2" in the file name) currently available from the LF website.