NatureServe Riparian Vegetation, DRECP 12km buffered boundary

The dataset represents the work of multiple states and Federal agencies as part of the US Gap Analysis and LandFire programs. Multi-season satellite imagery (Landsat ETM+) from 1999-2001 were used in conjunction with digital elevation model (DEM) derived datasets (e.g. elevation, landform) to model natural and semi-natural vegetation. The minimum mapping unit for this dataset is approximately 1 acre. Landcover classes are drawn from NatureServe's Ecological System concept. Five-hundred and fourty-four land cover classes composed of 12 cultural and 532 Natural/Semi-natural types are described. Land cover classes were mapped with a variety of techniques including decision tree classifiers, terrian modeling, inductive modeling, and unsupervised classification. The 67 USGS mapping zones were modeled independently of one another by multiple spatial analysis laboratories. Following completion of the national data set each individual land cover type was evaluated by NatureServe through individual working groups and two regional workshops attended by State, Federal, and Heritage Program ecologist. Where individual systems were identified with likely errors a description was recorded of the issue and a fix where available was described and initiated by NatureServe. All changes are available in supporting documentation and represent the opinion of multiple experts.