Questions and Answers
Question: Is Tower Maps a repacking of the FCC data?
No, Tower Maps is not developed from the FCC Antenna Structure Registration
Question: What is the FCC data?
The FCC Antenna Structure Registration (ASR) Data is maintained by
the FCC from those site owners or carriers who submit FCC ASR
registration forms. The FCC data is free and it is what it is. The
FCC data is neither complete, not
always current. It is available in flat tables and needs to
be reworked for use in GIS. The FAA data is focused on aviation hazards and height
obstructions above 200 feet.
Question: How complete is the data?
Tower Maps is estimated to include over 98% of all commercially
viable antenna sites. This estimate for Tower Maps is based
on over 10 years experience of researching and compiling antenna site
data. Tower Maps does not include site such as single tenant
rooftop arrangements. The completeness of the FCC data is
substantially less than that of Tower Maps, based on visual overlay of
the two data sets. The ASR file currently contains 104,000 records
(as of August 2006) although many are not useable collocation sites.
The FCC believes that 28% of all registrations
are not yet filed. The LBA Site Assessment Project estimates that 70%
are not filed or are in error. (http://www.lbagroup.com/Wireless_University.php)
Question: What is the source for Tower Maps data?
Tower Maps is compiled directly from over 450 site owners data
Question: Are rooftop sites includes in Tower Maps and FCC data?
Tower Maps includes commercially managed rooftop sites. The
FCC ASR data does not include these as they are concerned with the
Question: What sites are not
included in FCC data?
There are many sites that are included in Tower Maps that do not
appear in the FCC ASR
data. This includes not just the small tower owners, but also the
large ones including Sprint Sites, American Tower and others. The
lack of FCC registration does not appear to be an issue of company size
or tower age.
Question: Aren't all towers properly registered with
Simply stated, no. As to why these towers are not properly
registered is unknown. These are obvious violations. Enforcement
of the registrations by the FCC is, no doubt, a difficult task.
Question: How is data maintained for current ownership?
Tower Maps is updated on a daily basis. The files are then
compiled directly from over 450 site owners data files for monthly
update release. When a site is bought and sold, over time the record
shifts from the original owners to the new owner. One will find
that there are "duplicate" sites in Tower Maps. The FCC data
simply reflects the antenna site original application and records are
Question: Is there a quality assurance review for spatial
Tower Maps data for consistently prepared for using decimal degrees
in NAD83 projection. Data received in NAD27
are reprojected. All sites are plotted and checked for transposed
or unrealistic latitude and longitude. Check plots are prepared
and sent back to site owners such that the site owner can correct
The FCC data does not appear to a Quality Control review or update
Question: Are there duplicate records in Tower Maps?
Yes, Tower Maps data does include some duplicates. There are two
primary reasons for this. One is a site which recently changed
ownership. Historically Tower Maps has worked to flush out
"sold sites". This includes scraping tower companies
that have been purchased by the larger tower companies. It has
been noticed over the years that this process can take month or
years. It is also noticed that after the transition, there are
often error introduced. The second reason is that several
companies work together, co-listing one another's sites. When
Tower Maps is able to identify the true site owner, duplicate records
Question: Are there error records in Tower Maps?
Unfortunately yes, Tower Maps makes all reasonable efforts to check
and scrub the data, but is reliant on the site owners providing accurate
data. For example, one site purchased by American Tower was
noticed to be on the wrong site of the road as seen in aerial photo (TerraServer).
AT then attempted to correct the location, but placed is 21 miles in the
wrong direction. This was confirmed in internet postings.
Question: What value does Tower Maps provide?
Tower Maps is value-added data providing the data subscriber with
an accurate, complete and current listing of available antenna sites in
a consistent GIS-ready data package.
Question: Where does one obtain FCC data?
You can download the FCC ASR data files in ESRI GIS shapefile format
free (10 MB zipped)...... click
You can purchase this data from Percon if you wish......
here and click here