There are 199 sheets in this series from which the 63 counties were built. Each county contains the registration tics for all of the sheets associated with that county. For example, Moffat County has 7 sheets. Each sheet will have between 4 and 6 tics. The number of tics per sheet was determined by how big the sheet was. If a particular sheet was physically too big to fit on the digitizer it was digitized in two segments and appended. Consequently, these sheets have 6 tics. All others have 4, the minimum required for processing as an ARC/ INFO coverage.
The labeling convention used for tics follows. Tics contain 4 numbers. The first two designate which county it is. These are numbered 1-63 and begin alphabetically: Adams-01 thru Yuma-63. The next number designates the sheet #. The final number is the tic number on the sheet. All tics were entered starting at the southeast corner and going clockwise.