The Hard Truth About GIS Mapping and E911

By Sam Wallace

by Sam Wallace, Digital Data Technologies, Inc.

In America today, public safety has become a paramount issue facing the nation.More than ever the public is relying upon the government to provide for and support any efforts to improve public safety services.At the very heart of public safety lay the 9-1-1 emergency dispatch systems of this country.Without 9-1-1, there is simply no emergency response.Thus, 9-1-1 is the keystone of public safety.

In November of 2001, the National Emergency Number Association (NENA) called a Critical Issues Forum in Columbus, Ohio for two days.The forum was called to bring some 200+ leading 9-1-1 officials in from all over the country to address the serious issues facing 9-1-1 in America, particularly in the wake of the recent homeland security issues.The core topic of the Critical Forum was the use of GIS mapping and Automatic Location Information (ALI) in E9-1-1.Particularly, the Forum was called to inform 9-1-1 officials what GIS is, how is it used, and what are the common problems and solutions the 9-1-1 industry has encountered concerning this GIS phenomenon.This article will endeavor to address those issues with attention and detail for anyone in the 9-1-1 and GIS fields who are encountering a lot of questions and uncertainties mapping 9-1-1 calls without much success in getting the answers they need.

GIS for E911: The basicsGIS has been able to revolutionize both private and public sectors in its ability to give decision makers information about their business and easily convey that information by displaying it in a visual, mapped format.Maps have fundamental applications such as the use of digital road maps for E9-1-1 emergency dispatch.However, often times the road (referred to as a centerline, meaning 'center of pavement') data used by E9-1-1 agencies is grossly inaccurate in terms of spatial location and naming while also not possessing any of the depth of information or "intelligence" that is required for the computer software to use the data to the degree that E9-1-1 needs.

The consequences of this problem are that there have been a great amount of preventable deaths across the county with the inevitable lawsuits that follow.One of the largest contributors to these problems has been the use of cell phones for E9-1-1 emergency assistance calls.Though E9-1-1 agencies have enough trouble locating and mapping calls from permanent addresses, locating the free roaming cell phone has been an immense challenge that has tripled the reliance on good, accurate, and intelligent centerline basemaps.

A warning about GIS data used for E9-1-1
A large misconception 9-1-1 officials need to be aware of concerning GIS is that the mere purchase of GIS software does not mean an agency has a GIS, or even a good one for that matter.GIS is a holistic system where computer software effectively uses geographic data to relate information and aid decision-making.Without the data, there is no GIS! Examples of geographic data are: Road Centerlines, Address Point Locations, Emergency Service Number (ESN) Zones, Police/Fire Jurisdictions, Digital Aerial Photography, Municipal Boundaries, Water Features, etc.

Some of these data sets are available for purchase, while others are available for free via the government or do not exist at all and require generation from scratch.Regardless of where the data comes from, great differences can exist in the quality of that data.And the hard truth about GIS data being used for E9-1-1 is that a very ugly pattern has emerged showing that the cheaper the data, the more unusable for E9-1-1 it is.

County E9-1-1 Agencies are withholding payments to Computer Aided Dispatch (CAD) companies because the street centerline data they furnish is unusable.The reason for this pattern is that cheap or free data sets do not have the level of detail and accuracy to support the business of saving lives in a specific jurisdiction.

Geographic data is the heart and soul of a GIS, and the quality of that data determines the value of the system as a whole.In the GIS world, this idea is summed up in the term, "Garbage In, Garbage Out." Or rather, if one uses garbage data, garbage is all they will get out of their GIS ...a potentially dangerous situation with E9-1-1.The quality of GIS data is determined by the methods and techniques used to collect or develop that data.The very idea of data failure in E9-1-1 services is half the reason why the recent NENA Critical Issues Forum was called.


The method by which the emergency service sector is either using or waiting to use in the location of wireless 9-1-1 calls is to take Automatic Location Information (ALI) associated with each wireless call and relate that information with the GIS mapping.In essence, the ALI is latitude and longitude coordinates of where the call originates.With those coordinates, emergency dispatchers can geographically reference the location on a map.

The key issues of the NENA Critical Issues Forum, concerning the use of GIS mapping and ALI in E9-1-1, were: centerline and address data quality, widespread use of poor data, integration into existing 9-1-1, and data maintenance.At this time, it is accepted that the use of cellular phones for 9-1-1 emergency calls is not only going to remain as a phenomenon in emergency service, but is also projected to increase, at least initially, at an astronomical rate.

Therefore, the discussion of these topics is neither idle nor avoidable.Once the FCC mandate for ALI latitude and longitude coordinates of cellular distress calls become a reality in the United States, emergency service agencies are going to have to scramble (if not already) to put this information to work with success.Therefore, each issue, as discussed above, is critically important in that any can single-handedly cause E9-1-1 systems to fail at locating and mapping a cellular distress call.

Data Quality Issues

The issue of centerline and address data quality/widespread use of poor data is a situation that has been sweeping across the country with wildfire speed and affects both wireless and wireline E9-1-1 services.Essentially, lack of expertise and funding force emergency service agencies to accept and attempt to implement GIS software and data that is of poor quality whether it be from a CAD vendor, a telecom, or a "chop shop" engineering firm.The results are an inability to integrate with an existing system, and/or a failure to successfully map both wireline and wireless distress calls.

What constitutes poor data, particularly centerline and address data, are gross inaccuracies of where roads and addresses occur on the earth, inaccuracies in road naming contained in the E9-1-1 databases, as well as giant holes and omissions within both the road and address inventories of the E9-1-1 databases.

The core of this problem is that the E9-1-1 applications of GIS require extremely detailed data sets of any given jurisdiction.There are a great many data sources there that appear to be useful to an emergency service agency.Due to accuracy requirements, many of these data sources are insufficient for the intense and specific use of 9-1-1 distress call mapping, and therefore fall short in many different and pivotal areas of criteria.

Unfortunately, these various sources of GIS data are the most inexpensive (if not free) and are being pushed by large vendors with little knowledge or concern of the role the data will play in E9-1-1.The unfortunate results are that a great many emergency service agencies are finding themselves in a nightmarish situation where their GIS mapping is either severely inadequate or dysfunctional, with accrued costs that effectively discourage any additional efforts to obtain proper mapping data either financially or politically.

Integration of GIS Mapping into Existing E9-1-1 Systems

The integration of any GIS data into an existing 9-1-1 system can be a potentially sticky situation.There is a general shortage of quality GIS expertise in the CAD industry.The unfortunate result of this particular scenario is that a great many 9-1-1 agencies opt to stay with a long time CAD vendor who is making the attempt to write GIS software components with their CAD products.The result is that the agency remains with the vendor until the product that either does not work at all, or works poorly.

The key to integrating GIS into an existing system is to find the GIS solution that is not dependant upon any particular CAD.This concept affords an E9-1-1 agency two options.One, the two software programs do not have to be housed under the same package, and can be implemented as separate entities that compliment each other indirectly.Or, find a GIS solution that can be delivered in an open format, which can be easily converted and implemented into any mapping software, whether it is mapping software a CAD vendor developed or GIS mapping software that has been developed specifically for E9-1-1 applications.

The integration of GIS mapping into an existing E9-1-1 system can be a relatively painless experience with great benefits as long as an E9-1-1 agency does its homework and research.In any given state, ask around and find out who has been successful in integrating GIS mapping with their E9-1-1 system and who hasn't.Find out what the pitfalls and traps are to better avoid them.Find out what methods have worked well so as to model them.Seek out GIS talent either at the governmental level or in the private sector.

Many county governments have GIS coordinators who can help guide the process and enlist the financial support of other county official's.Often, the data are valuable across several county departments and thus the cost can be shared.Be aware that your county may already have software, data, and personnel to facilitate the project.

From numerous personal observations, "low-balling" a project with unqualified personnel in the attempt to either build or integrate GIS mapping into E9-1-1 can easily set a county government back 5-10 years with untold monetary costs ...another unfortunate hard truth about GIS, whether it be in the effort of E9-1-1, or even in the pursuit of more traditional governmental roles.

Several firms and emergency service officials, such as Mark Berryman of the Greater Harris County 911 Emergency Network in Houston, Texas and Capt.Kathryn Stevens of the Allen County Sheriff's Ft.Wayne, Indiana were asked to present at the NENA Critical Issues Forum to help educate the panel about the uses of GIS with 9-1-1 as well as highlight problems and pitfalls to look out for.Contact either NENA (800) 332-3911 or the author to learn more about these real-life success stories.

Data Maintenance

Data maintenance becomes a key issue once GIS data is successfully implemented into an E9-1-1 system.The core concept behind this issue is: what good is GIS mapping if it is out of date and does not reflect road/address changes or developments within a jurisdiction? An emergency service agency can quickly find itself right back where it started from if diligent procedures for the frequent updating, correcting, and verifying of street and address data are not set in place and adhered to.Granted many jurisdictions do not undergo a great wealth of development per year, however, some jurisdictions can double their size in less than 6 months.Therefore, the issue of maintaining databases becomes paramount.

There are two ways of maintaining E9-1-1 databases.One, is to implement procedures in-house that enlist jurisdictional personnel who work closely with address and road inventory data, to ensure the proper changes and updates are made to the databases and funneled into the E9-1-1 system.This method can be more timely and accurate for database maintenance, but requires total cooperation across several internal departments.This can be difficult to organize and preserve in the face of political climates that could be initially negative while also ever changing.

The other option is to outsource the maintenance to a GIS data collection firm who specializes in the capture of new address and road information.This second option, however, does not account for any changes that are made within the existing databases.In addition, the data collection firm has to be able to deliver updated information that conforms exactly to existing data in terms of formats, depth, and accuracy with relative frequency and timeliness.Hence, selection of just such a firm would have to be extremely shrewd and informed.

With those options for GIS data maintenance in mind, each jurisdiction is going to have to decide what level of maintenance is necessary to ensure the integrity of E9-1-1 databases and upon the individual levels of growth and need.But in the end, the issue of data maintenance is something that is not going to go away, and will have to be a constant and regular operation.

The Future of GIS and E9-1-1

The road to utilizing GIS mapping with E9-1-1 for both wireless and wireline distress calls is not necessarily an easy or pleasant one.However, the benefits of such integration heavily outweigh any headaches that may come out of putting it into action.The 9-1-1 industry must realize is that it must learn the complexities of GIS data and system management.The talent and expertise exists in the to help make the idea of mapping distress calls, as well as other advanced emergency response issues, a true reality.However, the challenges involved with system implementation need to be understood fully in order to avoid what has happened to many public emergency response agencies already.Remember, in the world of GIS, two hard truths exist:

  • 1. GIS mapping is only as good as the data that drives it, and,
  • 2. You get what you pay for.When these two ideas are tossed into the business of saving lives, the consequences become readily clear.

Sam Wallace, GIS/GPS Specialist for Digital Data Technologies, Inc, is submitting the article.With a Geography from Wittenberg University and a Geography from Ohio University, he has 5 years experience working in the fields of GIS/GPS/Transportation Planning for both Government and Private Sectors.He can be reached at .(JavaScript must be enabled to view this email address), (614) 429-3384.

Published Wednesday, February 20th, 2002

Written by Sam Wallace

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