According to the National Emergency Number Association (NENA), a Public Safety Answering Point (PSAP) is a facility equipped and staffed to receive 9-1-1 calls. The service area is the geographic area within which a 911 call placed using a landline is answered at the associated PSAP.
This dataset only includes primary PSAPs. Secondary PSAPs, backup PSAPs, and wireless PSAPs have been excluded from this dataset. Primary PSAPs receive calls directly, whereas secondary PSAPs receive calls that have been transferred by a primary PSAP. Backup PSAPs provide service in cases where another PSAP is inoperable.
Most military bases have their own emergency telephone systems. To connect to such system from within a military base it may be necessary to dial a number other than 9 1 1. Due to the sensitive nature of military installations, TGS did not actively research these systems. If civilian authorities in surrounding areas volunteered information about these systems or if adding a military PSAP was necessary to fill a hole in civilian provided data, TGS included it in this dataset. Otherwise military installations are depicted as being covered by one or more adjoining civilian emergency telephone systems.
In some cases areas are covered by more than one PSAP boundary. In these cases, any of the applicable PSAPs may take a 911 call. Where a specific call is routed may depend on how busy the applicable PSAPS are (i.e. load balancing), operational status (i.e. redundancy), or time of date / day of week.
If an area does not have 911 service, TGS included that area in the dataset along with the address and phone number of their dispatch center. These are areas where someone must dial a 7 or 10 digit number to get emergency services. These records can be identified by a "Y" in the [NON911EMNO] field. This indicates that dialing 911 inside one of these areas does not connect one with emergency services.
This dataset was constructed by gathering information about PSAPs from state level officials. In some cases this was geospatial information, in others it was tabular. This information was supplemented with a list of PSAPs from the Federal Communications Commission (FCC). Each PSAP was researched to verify its tabular information. In cases where the source data was not geospatial, each PSAP was researched to determine its service area in terms of existing boundaries (e.g. city and county boundaries). In some cases existing boundaries had to be modified to reflect coverage areas (e.g. “entire county north of Country Road 30”). However, there may be cases where minor deviations from existing boundaries are not reflected in this dataset, such as the case where a particular PSAPs coverage area includes an entire county, and the homes and businesses along a road which is partly in another county.
Text fields in this dataset have been set to all upper case to facilitate consistent database engine search results.
All diacritics (e.g., the German umlaut or the Spanish tilde) have been replaced with their closest equivalent English character to facilitate use with database systems that may not support diacritics.
Use Cases: Use cases describe how the data may be used and help to define and clarify requirements.
1) A disaster has struck, or is predicted for, a locality. The PSAP that may be affected must be identified and verified to be operational.
2) In the event that the local PSAP is inoperable, adjacent PSAP locations could be identified and utilized.
ESRI ArcMap 9.1 ESRI ArcMap 9.2 ESRI ArcView 3.2Metadata written using TKME by Peter N. Schweitzer (U.S. Geological Survey, Reston, VA 22092) version 2.9.17 <http://geology.usgs.gov/tools/metadata/>
Metadata tested for compliance to FGDC-STD-001-1998 and converted to HTML using MP version 2.8.25 by Peter N. Schweitzer (U.S. Geological Survey) <http://geology.usgs.gov/tools/metadata/>
ID Check: The [ID] attribute is not blank and each of its values is unique.
Coordinate Check: Coordinates are not null or zero and the x and y fields match the shape.
Basic Address Check: Physical addresses were verified to be non blank and to not be a "PO Box", "General Delivery", "Highway Contract", or "Rural Route" address.
Highway Address without Type Check: Physical addresses containing the word "Highway" or "Route" were verified to also contain a type designator such as "State", "US", or "County", if one actually exists for the highway or route. These type designators are often missing from addresses, leading to confusion if more than one "Highway" of the given number exists in an area.
Basic Name Check: Entity name is not blank, is not the same as entity city, and has a minimum of 2 characters. Name does not contain punctuation characters that can interfere with database operations, such as " (quote) and * (asterisk).
Basic Phone Check: All phone numbers (including the area code) are ten (10) numeric digits. Alphabetic characters have been converted to the corresponding numeric digit.
City Check: Entity city is not blank and is found in the named places file within 25 miles.
County FIPS to State Compare Check: The County represented by the tabular FIPS Code attribute is actually in the state specified by the state attribute. Some records in this dataset have failed this check. Because the location of the primary PSAP for the district may be located in a different county and state than the county with the most coverage by the district, the [fips] attribute may not always match the state specified in the [state] attribute.
County Name to State Compare Check: The County represented by the tabular county name attribute is actually in the state specified by the state attribute. Some records in this dataset have failed this check. Because the location of the primary PSAP for the district may be located in a different county and state than the county with the most coverage by the district, the [county] attribute may not always match the state specified in the [state] attribute.
Phone Number Format Check: Phone numbers (including area code) were verified to be formatted as nnn-nnn-nnnn.
NPA_NXX Check: Area codes (sometimes called "Number Planning Areas", or NPA's) and central office codes (sometimes known as exchanges, or NXX's) were validated against data from the North American Number Planning Administration (NANPA). In some cases, NPA-NXX combinations did not show up in the NANPA data but were verified to work.
Area Code Distance Check: Area code (NPA) is valid and is within its area code Boundaries.
Zip Code Check: The zip code is five (5) or nine (9) numeric digits, is listed in the postal database, is in the same state as indicated by the entity's [STATE] attribute, and is not a PO Box only zip code.
County in Name vs. Geographic Location Check: The county name found in the name of the entity matches geographic location. Some records in this dataset may have failed this check. Please see the process description for a description of how the [county] was populated by TGS.
Zip City Check: The entity's zip code and its city were verified to match according to the USPS Address Information System (AIS).
Zip Code Distance Check: Checks to make sure that the entity is not too far away from its zip code boundary.
Geographic Spell Check: Words that appear in the entity name were checked against a Standard English word list (and Spanish word list for entities in Puerto Rico). Words not appearing in these standard word lists were then checked against names appearing in the Geographic Names Information System (GNIS) of geographic features that are located within 25 miles of the entity. Proper names were manually reviewed for correct spelling.
ArcMap 9.2's "Check Geometry" was run on this dataset. There were no findings. "Check Geometry" looks for the following problems:
*Short segment: Some segments are shorter than allowed by the system units of the spatial reference associated with the geometry.
*Null geometry: The feature has no geometry or nothing in the SHAPE field.
*Incorrect ring ordering: The polygon is topologically simple, but its rings may not be oriented correctly (outer rings - clockwise, inner rings - counterclockwise).
*Incorrect segment orientation: Individual segments are not consistently oriented. The "to" point of segment i should be incident on the "from" point of segment i+1.
*Self intersections: The interior of each part must not intersect itself or other parts. For a multipoint geometry, this means two of the points in the multipoint are in the same location (same x and y coordinate).
*Unclosed rings: The last segment in a ring must have its "to" point incident on the "from" point of the first segment.
*Empty parts: The geometry has multiple parts, and one of them is empty (has no geometry).
This dataset does not pass ArcMap 9.1's "Check Geometry"
Most military bases have their own emergency telephone systems. To connect to such system from within a military base it may be necessary to dial a number other than 9 1 1.
Due to the sensitive nature of military installations, TGS did not actively research these systems. If civilian authorities in surrounding areas volunteered information about these systems or if adding a military PSAP was necessary to fill a hole in civilian provided data, TGS included it in this dataset. Otherwise military installations are depicted as being covered by one or more adjoining civilian emergency telephone systems.
WHERE THE DATA CAME FROM:
Each state was contacted by TGS to determine an official source for PSAP locations. GIS data was gathered from states willing to share such data. In cases where states were unable or unwilling to share data in this format, TGS requested that the states provide a source for identifying the PSAP locations. Original TGS research was used to fill in missing information.
HOW DATA WAS PROCESSED: METHOD A: STATE SUPPLIED TABULAR DATA
1) If tabular data and boundaries were provided by individual states, TGS utilized all provided PSAP boundaries and tabular data. In most cases this data was used "as-is" without any modifications made by TGS. Only incomplete tabular data was verified by phone contact. This is referred to as "Method A1".
2) If only tabular data was provided by individual states, TGS utilized a combination of several boundary resources such as: TIGER (TIGER_Place_Boundaries and TIGER_County_Boundaries), Military Installations (installation_boundaries), Indian Reservations (ind_res_boundaries) and National Parks (nat_park_boundaries) to generate the extents of each PSAP. In most cases the tabular data was used "as-is" without any modifications made by TGS. Only incomplete tabular data was verified by phone contact. This is referred to as "Method A2".
METHOD B: TGS RESEARCHED TABULAR DATA
1) If tabular data was not provided by individual states, TGS utilized researched data and a combination of several boundary resources as shown Method A2. In most cases the tabular data was verified through alternate references. Any discrepancies in tabular data were then verified through phone contact. The extent of each PSAP boundary was also verified through phone contact. This is referred to as "Method B1".
2) If tabular data was not provided by individual states, but boundary extents were provided, TGS utilized researched data and the boundaries provided by the state. In most cases the tabular data was verified through alternate references. Any discrepancies in tabular data were then verified through phone contact. Most boundary data was not modified by TGS. This is referred to as "Method B2".
Oregon - Method A1
3) In some cases areas are covered by more than one PSAP boundary. In these cases, any of the applicable PSAPs may take a 911 call. Where a specific call is routed may depend on how busy the applicable PSAPS are (i.e.load balancing), operational status (i.e. redundancy), or time of date / day of week.
4) If an area does not have 911 service, TGS included that area in the dataset along with the address and phone number of their dispatch center. These are areas where someone must dial a 7 or 10 digit number to get emergency services. These records can be identified by a "Y" in the [NON911EMNO] field. This indicates that dialing 911 inside one of these areas does not connect one with emergency services.
5) Seaward boundaries were determined using the U.S. Bureau of the Census' U.S. State Boundaries file with a cluster tolerance of 50 meters.
6) Ran Check Geometry and Repair Geometry. These checks passed in ArcMap 9.2.
7) Gaps between simple geometries over a decimeter were eliminated.
8) Four digit United States Postal Service (USPS) zip code extensions were assigned based upon the USPS Address Information System (AIS).
9) County name and FIPS codes were assigned through a spatial join. In instances where on PSAP covers multiple counties, the county and fips with the largest amount of coverage is represented.
10) All text fields were set to all upper case.
11) Leading and trailing spaces were trimmed from all text fields.
If the name is unknown, TGS has attributed this field with the same information found in the [PSAP_NAME] attribute.
If the primary PSAP is unknown, TGS has attributed this with the same information found in the [NAME] attribute.