Original data were retrieved from Federal Communications Commission database in June 2000.
Latitude and longitude coordinates of tower locations were converted to NH State Plane Feet.
Additional tower locations were added by sending inventory forms to all New Hampshire
municipalities and to all known tower companies doing business in New Hampshire. Field
verification of tower locations performed on large sample (but not all) of data using digital
USGS topographic maps stored on laptop computer.
Subsequent updates to the data layer follow the pattern of: 1) reference to current FCC database,
available on-line at <http://wireless2.fcc.gov/UlsApp/AsrSearch/asrRegistrationSearch.jsp>;
2) verification of all towers in FCC database using high-resolution aerial photography from NH GRANIT.