Detailed Crosswalk between LTRM General Classification and USNVC 2017

This set of non-spatial tables provides a detailed link (crosswalk) between the general classification within Long Term Resource Monitoring (LTRM) land cover/use (LCU) geospatial layers and the U.S. National Vegetation Classification (USNVC), current as of April 2017. The Upper Mississippi River Restoration (UMRR) Program’s LTRM element has produced LCU data over the past three decades consisting of geospatial layers (maps) showing locations of vegetation and developed lands within the Upper Mississippi River System (UMRS). The LCU data layers contain a classification of 31 general classes specifically developed to meet needs and objectives of the LTRM element of the UMRR Program. Because the LTRM classification is consistently applied across LTRM data layers of the UMRS, crosswalks to other classification systems can consistently be applied by using each of the 31 general map-class codes as a common link. To meet Federal Geographic Data Committee (FGDC) standards, geospatial staff at the U.S. Geological Survey (USGS) Upper Midwest Environmental Sciences Center (UMESC) have previously developed crosswalks between the LTRM 31 general map classes and the USNVC, a classification that meets the National Vegetation Classification Standard (NVCS) which was adopted by the FGDC to promote consistency across federal agencies. The LTRM data layers based on the 1989, 2000, and 2010/11 aerial imagery sets have received crosswalks to the USNVC; however, the USNVC has changed considerably over the years and the application of the USNVC across the LTRM data layers is inconsistent. A major revision to the USNVC was completed in 2015, making any USNVC versions previously applied to LTRM data layers obsolete; the major USNVC revision included changes in classification organization, names, and codes. The 2015 version of the USNVC has been met with stability unlike years prior, particularly in the upper hierarchical levels of the classification, with only minor adjustments to lower hierarchical levels made in 2016. The crosswalk tables provided with this data set deliver an up-to-date version to the USNVC, current as of April 13, 2017. The set of crosswalk tables provides a detailed link between the LTRM 31 general map classes and lowest plausible hierarchical classification levels in the USNVC, and includes classification codes and names at all applicable hierarchical levels in the USNVC, which was a feature not included with previous crosswalk versions for LTRM data layers.