Understanding OAHP Data

OAHP data are compiled from projects on federal, state, tribal, local municipal, and private lands. The data entered in our systems reflect the recorder's interpretation of the resource. If a record is missing data, please refer to the original site form for more information. 

Site and survey data exported from OAHP's internal database are in a flat ASCII format with field delimiters set as ">".  Below is a listing of the spreadsheet columns along with an explanation of the data being exported.

OAHP GIS data are compiled from various sources: digitizing efforts by OAHP staff, buffered point locations from automated data imports, geolocation of addresses, and data imports provided by federal agencies and contractors. If data are detonated by the acronym 'BFD' or 'PEN' in the VER field of the GIS attribute table, these locations have not been checked for accuracy beyond the county level.

All sites (including isolated finds) and surveys are represented as polygons. In most cases, sites smaller than 5 acres are the result of buffered points based on a user-specified tolerance representative of the size of the site (default is set to 18m or .25 acres). Linear sites and surveys are buffered lines based on a user-specified tolerance to most accurately represent the width of the survey transect. If OAHP received shapefiles that represent the actual shape of the site or survey, that polygon is maintained as it was received regardless of the size of the site.

Sites and surveys larger than 5 acres are typically digitized as they are represented on maps submitted to OAHP. However, if information is received with poor or unclear spatial representation, these resources may be represented as buffered points or not mapped in GIS at all.

OAHP GIS data are projected in NAD 83 in either zone 12 or 13 depending on the location of the resource.