–Enumerator
records field extents, cover types, and acreage
•Every June, approximately 41,000 farms are
visited or called by enumerators as part of the June Agricultural
Survey.States that participate in the
Cropland Data Layer Program will have every field digitized by the NASS field
office staff or cooperating partners.
•The unit of observation is the tract, which may
contain one or more fields or land uses and represents a particular land
operator’s acreage within a segment.The
enumerators draws off field boundaries onto the National Aerial Photography
Program’s (NAPP) 1:8,000 scale black and white aerial photos where the
segment is located, according to their observations and the farmer reported
information.The fields are labeled
and the cover type is recorded using a grease pencil on the aerial photo.
•Enumerators account for every field/land use
type within a segment.They assign
each field a cover type based upon a fixed set of land use classes for each
state.Every field within a segment
must fit into one of the pre-defined classes.