USGS Gap Analysis Project - Additional Data – Hydrologic Unit Codes [HUCs]
Dates
Publication Date
2011-02-22
Citation
USGS - Core Science Analytics, Synthesis, and Library - Gap Analysis Project, 20110222, USGS Gap Analysis Project - Additional Data – Hydrologic Unit Codes [HUCs]: U.S. Geological Survey, https://doi.org/10.5066/F7DZ0754.
Summary
The Hydrologic Unit Code (HUC) is part of a hierarchical classification system for surface water drainage in the US (Seaber et al. 1987). The numerical code represents a “cataloging unit” of delineation. Vector format (i.e. polygon) data were compiled from United States Geological Survey (USGS) source - the Watershed Boundary Dataset (WBD). For this project the dataset was modified by removing duplicate codes, removing duplicate polygons, and editing the line work to include near shore habitats in both the coast lines and within large water bodies. The coastal polygons were expanded 5 kilometers from landward edges to create a consistent coastal boundary. This altered 12-digit code HUC dataset was used to delineate species ranges as [...]
Summary
The Hydrologic Unit Code (HUC) is part of a hierarchical classification system for surface water drainage in the US (Seaber et al. 1987). The numerical code represents a “cataloging unit” of delineation. Vector format (i.e. polygon) data were compiled from United States Geological Survey (USGS) source - the Watershed Boundary Dataset (WBD). For this project the dataset was modified by removing duplicate codes, removing duplicate polygons, and editing the line work to include near shore habitats in both the coast lines and within large water bodies. The coastal polygons were expanded 5 kilometers from landward edges to create a consistent coastal boundary. This altered 12-digit code HUC dataset was used to delineate species ranges as part of the USGS Gap Analysis Project's species range and distribution modeling effort. This HUC data set is considered official foundational data for the GAP species modeling process. The data have been made available provisionally to enhance understanding and use of GAP species data.
Additional data, such as this HUC data, are used in the GAP species modeling process. The altered 12-digit HUC dataset was used to delineate species ranges as part of the modeling process.
