This is the process that was used by the data conversion vendor to take the property data from mylar to digital. Mount mylar on digitizer and register. Get Root Mean Square (RMS) better than 3.5 feet. Digitize tile neatline. Digitize all data from source mylar. Overlay street name mylar. Capture all street names and additional line work. First quality check of digital data. Each file was plotted and checked for accuracy by overlaying plotted digital data on mylar sources. All interior data and data up to one inch outside the neatline is checked. Code linework so it will be the proper entity on the map. Code annotation so that each text will go into the proper layer. Code points so they will be the correct symbol (Church, School, etc, etc.). Line attribution and polygon building. Code linework correctly for map display. Code polygon correctly so that the data goes into the correct region subclass in ArcInfo. Automated data cleanup. This includes removing overshoots and undershoots, breaking all lines at intersecting lines and rotating annotation with 15 feet at a line to the same angle as the line. Perform on screen best fit of the data using planimetric data as a reference. Keep individual parcel distortion to a minimum. Parcels less than one acre should not be altered more than 10 feet. Parcels more than one acre should not be altered more than 20 feet. Do block adjustment. Edgematch data with surrounding tiles. Lines must be snapped. Polygon attribution must be identical. Deleted problems are logged, researched and corrected. Quality assurance check is performed on best fit composite data. Mark up and directives for actual placement are noted by reviewer. GIS technician adjusts data as noted. Translation from APS to ArcInfo. Regions are built and the data is translated. Second quality check. ArcInfo data was plotted and overlaid on source mylars to review the overall quality and consistency. If changes are needed the files are fixed in APS, retranslated and replotted. Second pass of automated data cleanup. This is to be sure editor did not introduce any new errors. Composite data is merged into extracted data. Topology is built and data is attributed and annotation is constructed. Check is preformed for topology and label errors. Quality control program is run by GIS technicians. Data is submitted for final review and acceptance.
Plat documents are received in the GIS and Mapping Services office. The document is reviewed for control with NAD83, deed reference confirmation, and reconciliation of volume and parent parcels. Parcel identifiers are assigned to the parcels. Double circle (subdivision number) are determined. Documents are processed by discarding any preliminary plats, pins entered into Masterparcel tool, distribution of assessment copy, and folder prepared for GIS analyst. Quality control procedures are performed by reviewer including visual inspection, attribute check, and validity check. If no errors are found data is posted to the database. If errors are found returned to GIS analyst for corrections.
This layer contains polygons. Each feature contains the parcel identifier (PIN). The PIN structure can be located on the Fairfax County web site (http:). The feature also contains the date in which it was added to the database.