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Next Generation 911 GIS Resource Hub


Welcome to PEMA’s comprehensive Geographic Information System (GIS) resource hub! Here, our GIS partners should find everything they need to help their county Public Safety Answering Point (PSAP) complete the necessary transition to Next Generation 911 (NG911) service.


Chapter 53 of Title 35 requires that all counties build and maintain a set of NG911 GIS layers that meet a robust set of public safety grade quality standards, are aligned to PEMA’s NG911 GIS Data Model, and are ready to enable geospatial call routing at the time of cutover to NG911 service.

The required sets of GIS layers are:

  1. Emergency Service Boundaries for fire, law enforcement, and EMS (separate layers are needed for each service type)
  2. Provisioning Boundary
  3. PSAP Boundary
  4. Road Centerlines
  5. Site/Structure Address Points

Over the past several years, Pennsylvania’s counties have been diligently building and maintaining these required GIS layers ahead of their migration to NG911 service. With the transition to NG911 service now underway in the commonwealth, it is important that counties remain focused on closing any lingering gaps in their NG911 GIS data and are ensuring that their data will be NG911-ready ahead of their migration.

Goals and Metrics

PEMA’s primary GIS-related goal is that each county’s required set of NG911 GIS layers should be NG911-ready and capable of supporting geospatial call routing at the time of that county’s cutover to NG911 service.

To best support this function, it is important that a county’s NG911 GIS data meets these three metrics:

  1. Zero Critical Errors and Provisioning Errors are present
  2. ALI to Road Centerline layer synchronization rate reaches or exceeds 98%
  3. ALI to Site/Structure Address Point layer synchronization rate reaches or exceeds 98%

Within the commonwealth’s NG911 GIS framework, counties are responsible for building, maintaining, and regularly provisioning their NG911 GIS data to the commonwealth’s NG911 system using the GIS Data Hub (GDH) Spatial Interface (SI) solution.

Demystifying the GIS Data Hub Spatial Interface

It is worthwhile reviewing the role that the GIS Data Hub (GDH) Spatial Interface (SI) will play in the commonwealth’s NG911 system. As noted above, GDH will serve as the Commonwealth’s SI solution for NG911. It is built and maintained by GeoComm (PEMA’s vendor for NG911 GIS services) and GeoComm will provide ongoing technical support to counties after they have been onboarded to GDH.

The GIS Data Hub performs three essential core functions in the NG911 system:

1. Quality Control (QC):

Counties will be responsible for regularly uploading their NG911 GIS layers to GDH, starting after their regional onboarding training. Once GIS layers are uploaded, GDH will perform a robust set of automated Quality Control (QC) checks on the data. Immediately following a region’s GDH training session, counties will focus on making their data NG911-ready and will be utilizing GDH to measure and evaluate their progress. This process is expected to take several months and must be completed before a region is ready to migrate to NG911 service.

2. Data Merging/Coalescing:

Once a locally provisioned GIS data layer has cleared the QC process and meets the three metrics indicating GIS-readiness outlined above, it gets merged with corresponding layers that have also passed QC to create a regional layer. For example, imagine that a region consists of three counties: County A, County B, and County C. These counties, which were onboarded to GDH several months ago, have been identifying and addressing gaps in their NG911 GIS data. During their most recent round of edits, each of the three counties’ Road Centerline (RCL) layer became NG911-ready.

After each county uploads its updated RCL layer to GDH, each layer, being NG911-ready, will pass GDH’s set of automated QC checks. After clearing QC, GDH will recognize that each county’s RCL layer is NG911-ready and will automatically merge these three separate RCL layers into a single regional RCL layer. The result is an RCL layer that provides coverage for Counties A, B, and C. This process will be repeated for all NG911 required GIS layers within the region until there is a complete regional set of corresponding required NG911 GIS layers.      

Note: If a county introduces Critical Errors into their data after becoming Critical Error free, their submission will not be aggregated into the statewide set of NG911 layers until the Critical Errors are addressed. Counties should always review the QC reports generated by GIS Data Hub that accompany each upload to ensure all Critical Errors are identified and corrected.

3. Passing NG911-Ready Data into Next Generation Core Services (NGCS):

After a region’s data passes QC and is merged into a regional set of corresponding GIS layers, GDH then passes these NG911-ready regional layers into Next Generation Core Services (NGCS), thus enabling geospatial call routing. After a region is migrated to NG911 service, that region’s NG911-ready GIS layers will be merged with other migrated region’s NG911-ready layers. After all the commonwealth’s seven NG911 service regions have been migrated to NG911 service and have provisioned NG911-ready GIS layers to GDH, all counties within the commonwealth will have access to a comprehensive set of accurate, current, and authoritative statewide NG911 GIS layers that provide statewide coverage. These layers will continue to be maintained at the county level and be regularly provisioned to GDH.

As updates are made to data at the local level, following regular provisioning to GDH, these updates will be reflected in the statewide layers, ensuring that the statewide NG911 GIS layers remain accurate and up to date.

Quality Control Pre-Check Program

If your county is in a region still waiting to be onboarded to GDH but would like to get an early preview of your GIS data’s NG911-readiness, consider participating in PEMA’s voluntary NG911 GIS Quality Control (QC) Pre-check Program. This free program allows counties that are not yet onboarded to GDH to run their current NG911 GIS data through the GDH’s set of QC checks.

Participants will receive an updated QC report that identifies any Critical or Provisioning Errors. PEMA and GeoComm technical staff will then host a follow up one-on-one call to go over your results and discuss strategies for reducing your total number of Critical and Provisioning Errors ahead of your formal onboarding to GDH.

This program is designed to provide PEMA’s county GIS partners with a head start in evaluating and updating their GIS data’s overall NG911-readiness.

NG911 Migration/GIS Workflow Overview

To support a logistically efficient statewide migration to NG911 service, PEMA grouped all counties within the Commonwealth of Pennsylvania into seven NG911 regions. While each region will be migrated separately, it is important to note that each region will follow the same general approach for migrating to NG911 service. The map below shows each region with its target migration completion date. Please note that these target dates are subject to change.

 Map showing Pennsylvania's NG911 Service Regions

PEMA, GeoComm, and Comtech (the commonwealth’s NG911 service provider) will be working with counties region-by-region to facilitate the statewide migration to NG911 service.

Phases of NG911 Migration for GIS

Graphic of the phases of NG911 Migration for GIS

Expand AllClick here for a more accessible version

​1.  Pre-onboarding

​2.  GIS Data Hub (GDH) Training

​3.  GIS Data Starts Undergoing Continuous Quality Improvement

​4.  Regional GIS Kickoff Call

​5.  Monthly GIS Checkpoint Calls

​6.  Migration to NG911 Service

​7.  Ongoing Maintenance