U.S. Geological Survey (USGS) Gap Analysis Project (GAP), 2020, Protected Areas Database of the United States (PAD-US) 2.1: U.S. Geological Survey data release, https://doi.org/10.5066/P92QM3NT.
Summary
As an aggregated inventory, PAD-US contains thousands of spatial data sources integrated into one combined database. The policy of USGS is to integrate agency source data boundaries “as is” and translate attributes into the PAD-US format. Boundaries created by a specific agency or data steward may not fully align with those of another, creating GIS topology errors (mostly minor boundary discrepancies) associated with fee parcel ownership. In addition, more than one agency may submit an area for PAD-US without complete or accurate attributes to differentiate the fee owner and land manager. The FGDC Federal Lands Working Group (FLWG, https://communities.geoplatform.gov/ngda-govunits/federal-lands-workgroup/) and the PAD-US Team made [...]
Summary
As an aggregated inventory, PAD-US contains thousands of spatial data sources integrated into one combined database. The policy of USGS is to integrate agency source data boundaries “as is” and translate attributes into the PAD-US format. Boundaries created by a specific agency or data steward may not fully align with those of another, creating GIS topology errors (mostly minor boundary discrepancies) associated with fee parcel ownership. In addition, more than one agency may submit an area for PAD-US without complete or accurate attributes to differentiate the fee owner and land manager.
The FGDC Federal Lands Working Group (FLWG, https://communities.geoplatform.gov/ngda-govunits/federal-lands-workgroup/) and the PAD-US Team made considerable progress in reducing boundary discrepancies between federal fee land datasets in PAD-US versions 2.0 and 2.1. Work to edit source data and reduce overlaps between federal and state owned lands continues with the long-term goal of a topology error free (no gaps or overlaps) PAD-US Fee layer. The PAD-US geodatabase has a number of feature classes that overlay one another - for example, some easements overlay fee lands or other easements; many designation or proclamation boundaries overlay fee and/or easement lands, as well as other designations/proclamations. These are not errors - they are an accurate representation of the U.S. protected areas network but they can create challenges for spatial data analysts.
USGS added the Designation feature class to the PAD-US 2.0 geodatabase schema to remove overlapping management designation boundaries (e.g Wilderness Area) from the Fee feature class. This significantly improved the utility of the PAD-US Fee layer; however, some overlapping boundaries remain. Users and data-stewards are encouraged to generally review these overlaps, available in the Topology Assessment download attached in this record or through topology web services in the PAD-US Viewer: https://maps.usgs.gov/padus/. The assessment identifies all overlaps (minimum distance between feature coordinates to evaluate overlap relationship = 0.05 meter), large (greater than 5 acres), and small (less than 5 acres) overlaps between federal agency lands and between federal and state agency lands in the PAD-US 2.1 Fee feature class.
To assess and identify overlapping boundaries that remain in the Fee feature class of the PAD-US 2.1 geodatabase for users and data stewards.
Rights
DISCLAIMER FOR PROVISIONAL DATA: These data are preliminary or provisional and are subject to revision. They are being provided to meet the need for timely best science. The data have not received final approval by the U.S. Geological Survey (USGS) and are provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the data.
