Why NG9-1-1 GIS Data Can Never Be Truly Complete

June 5, 2019

Municipalities, counties and states seeking 100 percent accuracy in their geographic information systems (GIS) data may just be looking for the proverbial needle in a haystack.

The accuracy numbers most stakeholders consider acceptable hover around 98 percent. Houses go up, new neighborhoods go in, industrial parks are born, roads are altered, natural disasters alter the landscape and essentially all locations that cater to humans are in a constant state of flux. So 98 percent accuracy sounds laudable and, in reality, works quite well for the existing GIS systems used in public safety.

But in the case of next generation 9-1-1 (NG9-1-1), the accuracy of GIS data must exceed 98 percent, and here’s why: NG9-1-1 standards require a certain level of data quality when that GIS data is being provisioned into the Emergency Services IP Network (ESInet). GIS data accuracy of 98 percent or lower  cannot adequately meet requirements for other public safety answering point (PSAP) systems used. Achieving beyond the 98™ percent accuracy, public safety organizations can support all PSAP systems moving forward.

Boundary concerns
Boundary gaps are one of the primary concerns around data accuracy. When boundary data is not accurate, it can have major impacts on how an emergency call is routed. As the National Emergency Number Association (NENA) Data Management Committee’s GIS Data Stewardship Working Group outlined in its “Information Document for GIS Data Stewardship for Next Generation 9-1-1” last fall, GIS data is “at the heart of NG9-1-1 systems. Civic addresses associated with fixed caller locations are validated against GIS data to ensure that they can be mapped. When an emergency call is made, it is routed using the caller’s location along with the GIS boundaries of responder agencies to determine the correct responder.”

What that means is when boundaries are unclear – such as unintended gaps and overlaps between PSAP and other emergency services boundaries – problems crop up. Consider, for instance, town borders: in some areas, streets may form the border line between towns, or may wind in and out of a border, making assigning first responders to calls difficult.

According to NENA’s GIS Data Stewardship Working Group, “The Next Generation Core Services (NGCS) that validate addresses and route calls in NG9-1-1 systems are the Location Validation Function (LVF) and the Emergency Call Routing Function (ECRF), respectively.” LVF and ECRF rely on and use GIS data for address validation with caller locations and spatial queries so calls are directed to the correct responding NG9-1-1 PSAP. This underscores the importance of the accuracy and ongoing maintenance of the PSAP boundary layer. As a company, DATAMARK has been heavily involved in NENA workgroups:  Sandy Dyre is co-chair of the Real-Time Text (RTT) and is part of the NENA/APCO/CTIA/PSAP Location Accuracy Group; Jeff Ledbetter is co-chair of the GIS Data Transition; and Chris Robinson is a part of the Managing & Monitoring NG9-1-1 group.

If public safety systems are not synchronizing their GIS data at higher than 98 percent accuracy –  particularly in terms of boundaries –  call routing errors in certain instances are possible, including misdirected calls. In some instances, a misdirected call may mean the difference between life and death. Unless and until the NG9-1-1 Data Stewardship standard is updated, the industry will not have true operating procedures for how to meet the requirements that NENA has laid out for next gen 9-1-1.

ESInet specifies that source GIS data must clarify boundaries and centerlines between PSAPs and more. This data cleansing is important, and we outline some of the means to do so here. It’s all designed to help NG9-1-1 systems be the best and safest they can be. To learn more about how DATAMARK can help with both technologies and consulting services, contact us.

By: Stephanie McCowat

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