GeoPackage of Seabed Hazards for Offshore Infrastructure, U.S. Atlantic and Pacific Continental Shelves

Records were included which contain interpretable content, defined as qualitative or quantitative information that supported classification of one or more hazard types based on their attribute definitions. Supporting context could be explicit (e.g., direct identification of a hazard) or implicit (e.g., inference from mapped features, figures, or results). Hazard types were assessed independently and assigned only when sufficient evidence supported classification. Notes fields contextualize the basis for each classification. 'NA' indicates that data were insufficient for classification of that hazard, not the absence of the hazard.
Spatial domains represent an approximation of the interpreted extent of the study area and should not be assumed to precisely reflect the specific location or distribution of hazards. Where source material constrained the spatial footprint more narrowly (e.g., to a specific transect or feature), this detail is reflected in the notes field. All domain creation methods were recorded in the DOMAIN_M field.
Domain approximations are captured by the processing steps in DOMAIN_M. To provide an example, in the OI dataset, some domains were approximated on the location of individual infrastructure components (e.g., meteorological buoys or towers) when broader survey areas (e.g., SAP APEs) were not publicly defined. These points represent the reported location of the asset, not necessarily the center or bounds of the survey area. For example, the VOWTAP cable corridor was approximated using Marine Cadastre's 'Submarine Cable Areas' layer due to the absence of a publicly available 300-meter survey corridor.
Export Cable Corridor (ECC) domains were approximated using published features as detailed in the processing steps. Most ECC features were derived from the 'Offshore Wind - Export Cable Corridors (Proposed)' layer hosted on Marine Cadastre (version: December 21, 2023; coordinate system: GCS WGS 1984). An exception is the ECC for the Virginia Offshore Wind Technology Advancement Project (VOWTAP), which was based on the 'Submarine Cable Areas' layer (version: May 1, 2023; coordinate system: GCS NAD83) due to the absence of a publicly available 300-meter survey corridor.
OI_GHZD_Polygons: Contains 54 unique polygons. Each polygon is associated with a LEASE_NUMB, and multiple polygons can be associated with a single LEASE_NUMB value.
In the OI_GHZD_Table, unique areas are defined by a combination of the attributes 'LEASE_NUMB' and 'UNID_P'. For each unique combination, there are 34 separate 'GHZD' attribute enumerated values.
In the OI_GHZD_Table, a dependency applies to some of the GHZD attributes with respect to the identification of that feature. The attribute value for 'Bedform migration' has an attribute value set for IDEN if the following condition is met: one or more of the following GHZD attribute values has an IDEN value of 'Y' - Megaripples, Ripples, Sand ridges, Sand waves, Unclassified bedforms. However, it is possible for Bedform migration to have an IDEN value of 'Y', and none of those specific GHZD IDEN values of 'Y' depending on the source of information and what specificity is included in that source.
In a similar manner, the attribute value for GHZD Glacial till has the IDEN value set to 'Y' if that same comprehensive location has a GHZD Moraine IDEN value set to 'Y'. The presence of Glacial till does not necessarily mean the presence of a Moraine.
In the TD dataset, domain boundaries were interpreted from study extents - either mapped directly or inferred through georeferenced figures, descriptive text, or public feature layers. Where domain boundaries were not explicitly stated, generalized domains were created using consistent rules and documented as geoprocessing steps within DOMAIN_M.
For the TD dataset, sources were required to provide interpretations, except bathymetry. Bathymetric datasets were included even when unaccompanied by explicit interpretations, as they provide spatially continuous morphological context that can be readily reinterpreted to evaluate several hazard types.
In the TD table, whenever a DOI is available, the link to the source is the DOI link with one exception. For that one exception, the DOI link is a broken link that the publisher had not fixed by the time these data were released, hence providing the direct link to the publication (DOI is 10.2110/jsr.2020.69, publication link is https://pubs.geoscienceworld.org/sepm/jsedres/article/90/11/1510/593830/The-evolution-of-coastal-plain-incised-valleys).
In the TD dataset, although the Shape attribute geometry indicates ZM (implying both elevation and measure values associated with each vertex), this is erroneous. There are no Z or M measurements associated with polygon vertices and is a remnant of the original work through a file geodatabase. The decision was made not to attempt to “fix” the erroneous information at the final stages of release for fear of damaging the dataset and the ZM geometry designation does not impact the data use.
Although both the TD and OI datasets have values of 'Y' and 'NA' with reference to hazard identification, only the OI table uses the value of 'N'. The OI dataset can employ 'N' because the source material often explicitly states the negative occurrence of a hazard within a BOEM-approved system of characterizing hazards. In contrast, the source material used in the TD dataset were collected for a multitude of objectives using multiple techniques and, thus, do not systematically exclude the presence of specific hazards.