LANDFIRE (LF) National (2001) was the original product suite of the LANDFIRE program, which included Existing Vegetation Cover (EVC), Height (EVH), and Type (EVT). Subsequent refinements after feedback from data users resulted in updated products, referred to as LF 2001, that now served as LANDFIRE's baseline datasets and are the basis for all subsequent LANDFIRE updates. These updates account for disturbances and vegetation transition changes that may not represent current vegetation conditions. Therefore, in 2016 LANDFIRE initiated the Remap prototype to determine how to undertake a national-scale remap of the LANDFIRE primary vegetation datasets. EVC, EVH, and EVT were produced (circa 2015) via modeling for ecologically variable prototyping areas in the Pacific Northwest (NW) and Grand Canyon (GC). An error analysis within the GC suggested an overall accuracy of 52% (N = 800) for EVT, and a goodness of fit of 51% (N = 38) for percent cover (continuous EVC) and 53% (N = 38) for height (continuous EVH). The prototyping effort included a new 81-class map using the National Vegetation Classification (NVC) within the NW. This paper presents a narrative of the innovative methodologies in image processing and mapping used to create the new LANDFIRE vegetation products. Fire 2019, 2, 35 2 of 26 LANDFIRE (LF) 2001 was a joint 5-year project between the U.S. Department of Agriculture (USDA) Forest Service and U.S. Department of the Interior (DOI) to provide vegetation and fuel datasets for the conterminous United States circa 2001 [6]. A foundation for this suite of data products was the LANDFIRE Reference Database (LFRDB), which was developed to hold ground-referenced plot data information about vegetation types and structure metrics (i.e., height and cover). Data sources included Forest Inventory and Analysis (FIA), U.S. Geological Survey (USGS) National Gap Analysis Program (GAP), the Nature Conservancy, and other federal, state, and local datasets [6].Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) are the foundational geospatial datasets used by LANDFIRE. Descriptions of the Landsat bands and indices used by LANDFIRE are shown in Table 1a,b, respectively. TM and ETM+ images were not available cost-free during the production timeframe of LF 2001; however, LANDFIRE was a member of the Multi-Resolution Land Characteristics (MRLC) Consortium [8], which gave the program access to any previously purchased Landsat scenes. Landsat scenes not in the MRLC archive were purchased to meet the goal of three cloud-free images per Landsat World Wide Referencing System 2 (WRS2) Path/Row for the conterminous United States, Alaska, and Hawaii [6]. Additional remotely sensed data sources including a digital elevation model (DEM), slope, elevation, and biophysical gradients (e.g., temperature and precipitation) were also acquired or produced as needed.Classification and regression tree (CART) models were developed to determine vegetation types, while regression tree models were used to classify vegetation structur...