Segment Digitization/Editing
lJune Agricultural Survey (JAS) + Agriculture Coverage Evaluation Survey (ACES)
–Between 100 - 425 one square mile segments per state
–Use most fields for training classifier
lDigitize & label all fields in each segment
–Uses heads up on screen digitizing
lCompare digitized acres to JAS/ACES reported acres
–Check fields for accuracy & consistency on current years’ imagery
–Eliminate fields considered bad for training
•The segments are digitized in the field office using heads-up digitizing techniques, interpolating the enumerators drawing from the NAPP 1:8,000 photo of the segment, to the on-screen satellite image of the segment.  The digitizers are using satellite imagery from the previous growing season, as the crops from the current growing season have not fully emerged, and are not visibly separable during the JAS.  The fields are digitized using PEDITOR, and all of the segments in a state are managed by RSP to track segment production.
•Once digitizing is complete, all fields are labeled and a comparison is made to check for acreage validity between the digitized fields and the reported acreage.  Fields with variances greater than 10 percent when comparing the reported acreage (JAS) to digitized acreage, and fields smaller than 10 acres are both marked as bad for training.  If a field appears to be mislabeled or the reported cover did not emerge, an enumerator can revisit the site during the growing season and update the field level data, or the field can be marked off as bad for training.
•A spring and summer date of observation is preferred for maximum crop cover separation for multi-temporal analysis.  If only one date of observation is available (unitemporal), a mid summer date is preferred.
•If only an early spring date March-May or a fall date September-October is available (unitemporal) during the growing season, then it is best to not use that scene or analysis district for estimation, as bare soil in the spring and fully senesced crops in the fall will provide erroneous results.