This spatial dataset represents Border Patrol Areas of Responsibility 'in work'. This dataset is 'in work', meaning it is currently being updated. The AORs are variable by region. Each Border Patrol Sector is divided into Areas of Responsibility.

Border mileage for each Border Patrol station AOR is represented two different ways in the dataset.

GIS_MI = mileage derived from the geospatial length of the border boundary using the following projection:

USA Contiguous Equidistant Conic

MEMO_MI (Memo Mileage) for each station AOR is equivalent to GIS_MI (geospatial mileage) for each station AOR multiplied by the "Ratio" defined below.

Ratio* = Sector Memo Mileage (MEMO_MI) divided by the geospatial border mileage (GIS_MI) for each Sector. This ratio has to be calculated using the data in dhs.SDEOWNER.obp_sectors_dtl.

*Ratio for Rio Grande Valley = 0.986143

*Rio Grande Valley is a special case where the ratio was calculated using the following methodology:

*Rio Grande Valley Ratio = (316 miles from the MEMO) divided by geospatial border mileage (GIS_MI for zones 1 to 36) + 42.57 (Memo mileage for zone 37)

SQ_MI = square mileage was calculated using the following projection:

USA Contiguous Albers Equal Area Conic