| ACD |
Automatic Call Distributor - routes incoming 911 calls to the first available operator. |
| |
| Address Geocoding |
Process of assigning a street address to spatial data (such as points that represent structures). For example, an address may be matched to an address range on a street segment. |
| |
| ALI |
Address Location Identification - The ability to display the address of the phone from which 9-1-1 was dialed. Accomplished through preloading the telephone company's computer memory links with the proper information. Must have Automatic Number identification service installed before ALI can be installed.
|
| |
| ANI |
Automatic Number Identification - The ability to display the phone number of the telephone from which 9-1-1 was dialed in the same manner as ALI. Does not require ALI service installed.
|
| |
| Annotation |
Labels for data based on attribute values. |
| |
| APCO |
Associated Public Safety Communication Officials - Professional association which is used for up to date information on telecommunications and training.
|
| |
| ArcGIS |
A scaleable system of GIS software developed by ESRI that has several product levels with increasing GIS functionality. |
| |
| ArcInfo |
High-end GIS software produced by ESRI. |
| |
| ArcView |
A popular end-user GIS software produced by ESRI. It is available in two versions: ArcView 3.x, based on Avenue programming language, and ArcView 8.x based on Visual Basic programming language. |
| |
| Attribute |
A piece of data that describes a characteristic of a real world entity or condition. Attributes are either alphanumeric data or descriptive text strings. |
| |
| AVL |
Automatic Vehicle Location - A system that shows the position of response vehicles on a map display.
|
| |
| B9-1-1 |
Basic 9-1-1. An Emergency Telephone Number System using the digits "9-1-1" for access and routing all such calls to a staffed 9-1-1 Answering Point.
|
| |
| Base Data |
Basic level of map data on which other information is placed for purposes of geographic correlation. |
| |
| Base Map |
Mapped data that seldom changes and is used repeatedly. |
| |
| Cadastral Layer |
Information depicting the pattern of land ownership. The layer is typically based on legal descriptions. Also called a parcel data layer. |
| |
| Cadastral Mapping |
A mapping effort with ownership and value being the primary concerns. Used for tax analysis. |
| |
| Cartography |
The art and science of making maps. |
| |
| CDC |
Cooperative Dispatch Center - Two or more Public Safety agencies combined to share their communications resources.
|
| |
| Clip |
To limit the extent of a data set using an established boundary (such as a county boundary). |
| |
| COGO |
Coordinate Geometry – The set of mathematical tools and functions for encoding and converting bearings, distances, and angles into coordinate information. |
| |
| Control Point |
Points used to establish map coordinate control for uncalibrated objects. |
| |
| Conversion |
Data is reformatted from one file format to another during this process. |
| |
| Coordinate |
A value (X,Y, or Z) measured along an axis of a coordinate system. |
| |
| Coordinate System |
A reference system used to measure horizontal and vertical distances on a map. |
| |
| Coverage |
A GIS file format type created in ArcInfo.
Data–Information known about real world entities.
|
| |
| Data Dictionary |
Information about the defi nition and structure of data. |
| |
| Data Processing |
Procedures followed in a GIS to prepare data for display, attribution, and analysis. |
| |
| Database |
Collection of interrelated data sets stored together. |
| |
| DEM |
Digital Elevation Model - This term is used very generally to describe a great variety of terrain files and file formats. There are also a number of mutually incompatible file formats that use the .dem file name extension.
|
| |
| DLG |
Digital Line Graph - A USGS format, with several variations, for descriptions of individual data types such as transportation (e.g., roads), hydrography (streams, lake shores), and contours.
|
| |
| DOQ |
Digital Orthophoto Quadrangle - Aerial photography of the Earth's surface, usually provided in GeoTIFF form, but also seen in other formats. A DOQ for a 7.5-min., 1:24000-scale quad is huge, thus the common use of DOQQs--digital orthophoto quarter quadrangles. |
| |
| DRG |
Digital Raster Graphic - A scanned or digitally-created topographic ("topo") map just like you may have taken hiking. These usually come as indexed-color GeoTIFF files, sometimes in a .tar.gz file that includes an accompanying .tfw world file. |
| |
| E9-1-1 |
Enhanced 9-1-1. An Emergency Telephone Number System using the digits 9-1-1 for access and computerized procedures for automatic routing to the proper Law Enforcement Agency (Publication Safety Answering Point). E-9-1-1 includes ANI and ALI information.
|
| |
| Emergency Call |
A call routed to a PSAP reporting an incident, either in progress or just occurred, which presents a potential threat to life or property and which requires an immediate response from one or more public safety entities (law enforcement, fire, fire/rescue, EMS). |
| |
| EMS |
Emergency Medical Services
|
| |
| ENP |
Emergency Number Professional - a national certification through NENA.
|
| |
| ESN |
Emergency Service Number. A three-digit number which identifies jurisdictional boundaries. The 9-1-1 computer associates the ESN with the address and routes the call to the appropriate PSAP.
|
| |
| ESRI |
Environmental Systems Research Institute - GIS software company that produces the most widely used GIS software, including ArcInfo and ArcView. |
| |
| Exchange |
The three number prefix (first three numbers of a telephone number following the area code) which identifies the central office muting of the call. It appears on the Automatic Number Identification display as the second set of numbers, following the area code.
|
| |
| FCC |
Federal Communications Commission
|
| |
| FEMA |
Federal Emergency Management Agency
|
| |
| GDT |
Geographic Data Technologies - A company that produces/sells digital roads data sets with address ranges. |
| |
| Geodatabase |
An ArcInfo 8 data storage format. A geodatabase represents geographic features and attributes as objects and is hosted inside a relational database management system. |
| |
| GeoTIFF |
A special expanded version of the TIFF6 standard used for various purposes, especially for DRGs, that provides for embedding topographic information. Embedded geo-referencing removes the need for a companion world file, though one may be provided for compatibility. |
| |
| GIS |
Geographic Information System – Computer software and hardware designed to allow users to collect, manage, and analyze spatially referenced data. |
| |
| GNIS |
Geographic Names Information System- USGS digital point data that maps and names about two million physical and cultural features in the U.S. |
| |
| GPS |
Global Positioning System - A network of radio wave-emitting satellites. Ground-based GPS receivers use the satellites to derive accurate surface coordinates. |
| |
| Heads-up Digitizing |
Process of creating vector data using orthophotographs to define feature boundaries. |
| |
| Hotlink |
GIS function in ArcView that allows access to data and applications from within the software. |
| |
| Hydrography |
Water features, such as lakes and streams. |
| |
| Hypsography |
Contour lines. |
| |
| Internet Map Server (IMS) |
GIS software used to deliver (“serve up”) digital map data to an internet web site. |
| |
| Landline and Wireless |
Generalized terms used to distinguish Telecommunication Companies which provide hard wired telephones and those that provide Commercial Mobile Radio Services (CMRS), Personal Communication Service (PCS), or Cellular Radio. |
| |
| Latitude |
Angular distance in degrees of a point on the earth north or south of the equator. |
| |
| LIDAR |
Light Detection and Ranging- A dense
sampling of elevation points collected remotely
which can be used to create DEMs with high
accuracy levels.
|
| |
| Line |
GIS feature composed of a string of
coordinate values used to represent a linear
feature, such as a stream.
|
| |
| Longitude |
Angular distance in degrees of a point on the earth east or west of the Prime Meridian. |
| |
| Map Collar |
Open area around a map’s edge that contains the north arrow, legend, scale, and other map elements. |
| |
| Map Projection |
Method for representing all or part of the earth’s surface on a flat sheet. |
| |
| Map Scale |
The relationship that exists between the distance measured on a map and the corresponding distance measured on the earth’s surface. |
| |
| MapObjects |
ESRITM GIS software that can be used to build custom GIS applications. Uses Visual Basic programming. |
| |
| MDT |
Mobile Data Terminal - A computer which allows a field unit to send and receive messages from the communications center. A MDT can also be used to generate electronic reports.
|
| |
| Metadata |
Information describing a data set.
|
| |
| Mosaicking |
Process of combining separate orthophotographs into one image. |
| |
| MrSID |
Compressed image file format with .sid extension. |
| |
| MSAG |
Master Street Address Guide. The MSAG contains all of the streets and house number ranges in the E 9-1-1 service area. The streets and address ranges are assigned ESN’s to enable proper routing of 9-1-1 calls.
|
| |
| NAD27 |
North American Datum 1927, CONUS - Also called NAS-C (or sometimes just NAS), this datum is being superceded by NAD83 and WGS84, but is still very commonly found used for USGS 1:24000 DRGs and DEMs. |
| |
| NAD83 |
North American Datum 1983, CONUS - Also called NAR-C. |
| |
| NENA |
National Emergency Number Association - Professional organization with particular emphasis on 911. |
| |
| Network Analysis |
Analytical GIS techniques used to determine the relationships between locations on a network, such as the calculation of optimal routes through a road network based on distance or time. |
| |
| Orthophotograph |
An aerial photograph that has been scanned, rectified, reconstructed, and projected so distortions of geometry and perspective are removed. Also called an orthophoto. |
| |
| Orthoreference |
Process of adjusting vector data to align with features seen in an orthophotograph. |
| |
| PBX |
Private Branch Exchange - A telephone switch installed on a customer site. It defeats E-911 by not providing accurate ANI and ALI.
|
| |
| Photogrammetry |
The use of photography for mapping. |
| |
| Planimetric Map |
Map designed to portray the horizontal positions of
features.
|
| |
| Plat map |
Map representing property boundaries. |
| |
| PLSS |
Public Land Survey System - A grid system that divides surveyed land into blocks of 36 one-mile square sections called townships. |
| |
| Point |
GIS feature composed of one set of coordinates to describe its location, such as a well location. |
| |
| Polygon |
GIS feature that is a collection of lines that describe an area, such as a lake. |
| |
| PSAP |
Public Safety Answering Point - The agency responsible for the jurisdiction from which the 9-1-1 call originated and to which the call is routed.
|
| |
| PSDP |
Pubic Safety Dispatch Point - The agency location that is responsible for the actual dispatch of the call.
|
| |
| Q3 flood data |
Digital flood boundary data created by FEMA by scanning existing FIRMs (Flood Insurance Rate Maps). Designed to support planning activities, Q3 flood data should not be used to provide base flood elevation information. |
| |
| Quadrangle map |
The geographic area covered by a map. The standard quadrangle covers a 7.5’ x 7.5’ area. |
| |
| Raster data |
Data based on a grid system in which values representing different objects on the ground have been assigned to each cell. Examples include orthophotographs and DRGs. |
| |
| Rectification |
Removing geometric distortion from raster or vector data. |
| |
| Remote sensing |
The act of detection and/or identification of an object without direct contact. Includes aerial photos, satellite images, and LIDAR data. |
| |
| Resolution |
Level of image detail or sharpness determined by how many (pixels) compose an area of an image. |
| |
| Rubbersheeting |
Process in which raster data is stretched to match a new set of geometric constraints. |
| |
| Scanning |
Process of converting a paper map or photo to a digital image using a machine called a scanner. |
| |
| Shapefile |
A file format (.shp) used in ArcView GIS software to manage spatial data. |
| |
| Spatial |
Refers to features distributed in two or three dimensional space and having physical dimensions. |
| |
| Spatial Query |
Process of the extraction of map data using a specified area, such as a circle or other shapes. |
| |
| State Plane Coordinate System |
A coordinate system that defines map coordinates by zones for each U.S. state North-south extending zones use the Transverse Mercator projection, while those with east-west extent use the Lambert Conformal Conic projection. |
| |
| Tabular Data |
Data that is stored and manipulated in a digital table, such as a spreadsheet or database. |
| |
| TDD (TTY) |
Telecommunication Device for the Disabled - used to facilitate communications between deaf citizens and 911 operators, consists of typing text messages to and from the caller.
|
| |
| TIFF |
Tagged Image File Format - Color image file format used in multiple software products. |
| |
| TIGER files |
Topologically Integrated Geographic Encoding and Referencing files compiled and distributed by the U.S. Census Bureau. |
| |
| TMD |
Tactical Map Display - A computer screen which displays geographical information (streets and common places) to aid dispatchers.
|
| |
| Topographic Map |
Map that uses colors, symbols, and contour lines to represent generalized surface features. |
| |
| Topology |
Description of the relationships between point, line, and polygon features in vector data. |
| |
| TSP |
Telecommunications Service Priority - A program established by The Federal Emergency Management Agency that sets up priorities in restoring telecommunications service during a disaster.
|
| |
| Universal Transverse Mercator (UTM) System |
A grid system that
divides the earth’s surface into 60 zones which are 6° of longitude wide.
|
| |
| USGS |
United States Geological Survey - Federal mapping agency that produces DLGs, DRGs, and DOQQs. |
| |
| Vector Data |
GIS data structure for using point, line, and polygon features to represent objects on the ground. |
| |
| Wireless Phase I |
Phase I allows call takers to automatically receive the wireless call-back number, as well as deliver the location of the cell tower handling the call. |
| |
| Wireless Phase II |
Phase II allows call takers to receive both the caller's wireless phone number and their location information. |
| |
