CompassData Offers Enhanced 911 (E911) Expertise for Field Data Collection and GIS Mapping and Maintenance

CompassData specializes in the creation of accurate GIS base maps for Enhanced 911 (E911) applications. Road centerlines with accurate attribute information form the core of most E911 GIS databases. CompassData provides the equipment and staff to assist your agency in map creation and maintenance.

Our proven quality control processes ensure the accuracy of both positional data and attributes. CompassData will collect GIS features in the field and combine new data with existing data to create an enhanced base map for your GIS. This “feet on the street” approach ensures that your GIS and E911 data will be accurate and reliable.

E911 (E911) Related GIS Layers and Services:

Road Centerline Mapping and Addressing

CompassData utilizes GNSS equipped vehicles and aerial imagery (if available) to quickly and accurately capture road centerlines and related attribute information. Additionally, CompassData can verify your existing GIS data for accuracy and standards adherence, and merge it with the newly collected data, to create a complete street centerline base map with addressing. A completely addressed and networked road centerline map will allow you to geocode and route vehicles accurately and quickly.

Structure Mapping and Addressing

CompassData utilizes GNSS equipped vehicles, laser rangefinders, and aerial imagery (if available) to quickly and accurately capture structures and related address attribute information. A fully addressed and attributed structure map allows users to pinpoint landline 911 calls to a specific structure.

Cell Tower Mapping

CompassData has developed methods to quickly and accurately collect the position of cellular towers and their antennas. By using trained field personnel and sophisticated location devices, CompassData can deliver a product to help wireless carriers meet current FCC requirements.

Public Safety Boundaries

In addition to our strong GNSS cellular tower mapping skills, CompassCom has the ability to develop and maintain public safety boundary layers including:

  • Fire districts
  • Ambulance service boundaries
  • Law enforcement areas
  • Emergency service boundaries

This boundary information nicely supplements cell tower/site information, helping PSAPs to quickly and effectively dispatch correct emergency service personnel to all locations.


After completing the initial data collection, CompassData can maintain and update data for you. Given the increased growth and change that occurs throughout our communities, GIS base maps require constant updating and maintenance to ensure accuracy.

CompassData staff has experience working with local governments, emergency boards, and response entities regarding GIS updates to road centerlines, addressing MSAG to map comparisons, and other E911 related information.

Sample project: Larimer County, Colorado E911 Mapping.

More than 6,500 miles of road

  • Street Centerline
  • Address Mapping
  • Compiling Existing Data
  • Monthly Updates

GIS Database produced for the E-911 project in Larimer County, Colorado.


The E-911 Story

Fundamentally E911 works because a large, locally-based database of customer addresses called the Master Street Address Guide (MSAG) is queried whenever an emergency call is made. The 911 dispatchers use a digital map with addresses at their disposal.

Current FCC regulations dictate that all cellular providers support the location of emergency calls from their subscribers. The logistical problem in meeting this compliance regulation lies in that there is no address assigned to cellular phone numbers. A cellular call can originate from nearly anywhere.

In 2011, the FCC estimated that approximately 70 percent of emergency calls across the United States were placed from wireless cell phones, and the numbers are increasing. Unless the person making the call can give an explicit location to the dispatcher, it is very difficult to know where to send the emergency responders.

There are 3 fundamental methods for locating a cellular phone: handset and network-based solutions and a hybrid solution using both handset and network-based location data.

A handset location can be derived by integrating a sophisticated GNSS receiver in the phone and installing the infrastructure to route the latitude and longitude to the appropriate dispatch center. This method can be very reliable and accurate.

As an alternative, cellular carriers can opt for a network-based solution. The primary advantage of this type of technology is its independence of the handset.

Network-based location solutions work by triangulating a cellular phone's RF origin. The principal is very similar to locating the epicenter of an earthquake. If three listening sites pick up the disturbance, the location of its origin can be computed.

One of the critical variables in a triangulation solution is the X, Y, Z coordinates of the listening sites. Any errors in those coordinates will translate into errors in the position of the event. A cellular network solution is no different: the precise location of the antenna arrays must be known.

Related link: Federal Communications Commission (FCC) Guide to 911 Wireless Services

Here are some of the services we offer for Oil and Gas:

For more information on Oil and Gas Data Collection