As an aggregated data inventory, PAD-US contains thousands of data sources which are all integrated into one combined database. The policy of USGS is to accept agency data “as is” and translate them 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 attributes that 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 great progress with version 2.0 in reducing boundary discrepancies among federal agencies and between federal and state lands. PAD-US 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 reflection of the world of protected areas data. But they can create challenges for spatial data users.
In PAD-US version 2.0, designations and proclamations are in separate feature classes which has helped address this issue, but overlapping boundaries still remain in the fee parcel ownership layer desired for many applications. Users are encouraged to generally review these overlaps, available in the information contained in this record. 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 Fee feature class.
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