Recommendations:

• A key concept--the shapefile should be edited only to reflect changes in geography. Changes which do not affect the geography should be made to external data files.
• The number of fields in the shapefile attribute tables should be kept to a minimum.
• Recommended Database design (Table 1).
• Recommended Special Circumstances:

  a) Division of existing parcels--the new polygons must have different site ids from the original one in order to prevent duplicate records. As an example, if site 101 (80 acres) is split into two (20 acres and 60 acres), the new sites could be given site numbers 101a and 101b, but should NOT be given 101 and 101a, because of the external data associated with the original parcel. In this way the PMTSITEID (OIN/site id) can be used as the unique identifier for the new sites.

  b) Crop interplantings - a single polygon with one site id can be used to represent all interplanted crops on a single site, provided the crop name (or identifier) residing in an external table is used to differentiate between pesticide applications to one crop or another. In fact, the site id should be the same in order to identify the two crops as being grown in the same piece of ground.

  c) Subsequent crop plantings - should not require any editing of the shape file, since there are no physical changes to the boundaries, and hence neither the permit nor site ids change. As with interplantings, the crop name will be used to differentiate the applications.

• All other data pertaining to the permit or use reports should be stored in external tables, and the unique PMTSITEID used as the unique identifier to link or join the shapefile polygons to these tables.

The standardization of site identification numbers and the recommendations for site definitions and rules were approved by the County Agricultural Commissioners at the 1998 Winter Conference of the County Agricultural Commissioners and Sealers Association which was held in Sacramento.

Table 1. Production Agricultural Pesticide Use Site Locations shapefile Database Design Document.