Process_Description:
The first task was to create two uniform statewide indices for the North and South zones, with each index based on Pennsylvania State Plane Coordinate System, NAD 1983 (GRS80), with units in US Survey Feet. The ArcInfo Workstation GENERATE Command with FISHNET option was used to generate the 10,000' x 10,000' index grid. Command parameters are summarized in the table below:
Parameter,PA North Zone,PA South Zone
Lower Left Coordinate X (E),1,170,000,1,170,000
Lower Left Coordinate Y (N),-170,000,130,000
Upper Right Coordinate X (E),2,830,000,2,830,000
Upper Right Coordinate Y (N),790,000,1,090,000
Number of Rows (N/S),96,96
Number of Columns (E/W),166,166
An ArcGIS Python script was developed that assigned a tile name to each 10,000' x 10,000' tile. Per PGDSS version 2.0, the tile naming convention used to assign TILEID values was the upper left corner coordinate for the tile formatted as YYYYXXXXPAd, where name components are defined as:
? YYYY = the first 4 characters of the tile upper left corner Y coordinate
? XXXX = the first 4 characters of the tile upper left corner X coordinate
? PA = Pennsylvania
? d = N for North or S for South
In addition to TILEID, a ZONE attribute field was added to store values of [NORTH, SOUTH]. The attribute indicates whether a 10,000' x 10,000' tile falls north or south of the counties belonging to the state plane zone.