General Dynamics - Pathfinder Ad

9-1-1 Magazine: Managing Emergency Communications

Priority Dispatch

Navigator 2018




Stratus Technologies

CAD, NG911 & Records Management


Recording Systems


Facilities Planning and Design

First Contact 911

Training Trends & Tactics




Holland Co     
Mobile Command Vehicles



Houston-Galveston Area Council Launches GIS Replication for NG9-1-1

Date: 2012-08-02
Share |

A Case Study from H-GAC

The Houston-Galveston Area Council (H-GAC) is the regional planning agency for the 13 county region and it assists local governments in planning for the future.  Part of that preferred future involves making for a safer living environment that fosters a higher quality of life.  One way of achieving this is ensuring that when a 9-1-1 emergency occurs, police, fire and emergency services can find and respond to these situations in a quick and efficient manner.  In order to better assist our public services personnel and to make for a safer region, Data Services GIS has been able to standardize their 9-1-1 GIS database fields (schema) and adopt ESRI ArcGIS Server replication for their rural county 9-1-1 group as well as the public safety answering points (PSAP) within the region. Both of these tasks are geared to better equip H-GAC with assisting local governments respond quicker and more efficiently to emergencies – whether they be Fire, Police, or EMS.

The Houston-Galveston metropolitan area is currently experiencing both a job-market and population boom. Along with these comes the daunting task of providing the necessary geographic information data to the region’s public safety personnel.  In order to plan ahead for this need, H-GAC’s Data Services GIS Program Manager, Robert LaBarbera, and the 9-1-1 GIS Analyst, Rebecca Stoneman, have been implementing a system to share 9-1-1 GIS information with H-GAC and other governmental agencies both within and outside the region. Most importantly, the GIS database they have constructed over the past 5 years will be used as the base map for the Next Generation 9-1-1 GIS addressing system (NextGen) shared at the state level with the Commission on State Emergency Communications (CSEC).  The method by which the database is currently being shared and updated is called GIS geodatabase replication.

GIS geodatabase replication entails the transfer and synchronizing of a GIS database over either a local area network (LAN) or a wide area network (WAN).  In H-GAC’s case, the replication occurs over the Internet (WAN) with the region’s 9-1-1 county GIS network.  This network is composed of 8 rural counties that employ GIS coordinators who maintain information within their respective GIS systems.  H-GAC synchronizes the data from these rural counties up at the regional level and then replicates the data back down to over 23 PSAPs within the 13 county region.

Before the implementation of replication, some house cleaning needed to be done regarding the various data sets that were currently being used by the rural counties. In order for data to be replicated and shared throughout all agencies, a plan was needed to address how the region’s 9-1-1 GIS road and address point system would be combined within the H-GAC Enterprise GIS.  The following items were identified by Robert and Becky:

1) GIS data, which the 9-1-1 county coordinators used, needed to have the same database field names or schema throughout the region,

2) H-GAC’s GIS needed a way to send changes and receive digital updates from the 9-1-1 counties so that both the H-GAC GIS and the various county GIS sites shared the same synchronized data.

The initial item to tackle was the establishment of a unified 9-1-1 geodatabase schema.  The database schema is simply the layout of the various data fields that are contained within a database. Schema unification was tacked first since all database fields need to be the same if the information contained within the fields were to be transferred seamlessly between H-GAC and the counties. But, before delving into the schema solution, the history of multiple schemas will be addressed.

The history on multiple schemas are as follows: many years ago, when each county started maintaining address and road data, counties used whatever data fields their particular county needed at the time.  This data may not have included the same fields other counties used, simply because no agency had set a schema policy or enforced schema unification throughout the region. This is still the case today in many areas of the US but Robert and Rebecca both worked hard to get all the multiple county and city partners on the same page and to use the same schema.

First, Robert and the team initially worked with the Geographic Data Committee (GDC), Greater Harris County 9-1-1 and the City of Houston on what fields were needed for a regional 9-1-1 base map for the region.

Second, data requirements published by the National Emergency Number Association (NENA) and Texas’ CSEC were included in the database creation. The county GIS coordinators were also contacted in order to obtain their feedback on which fields should be included within the schema.  At the same time, a collaborative document titled, the “North Central Texas Council of Government (NCTCOG) Coordinated Statewide Geodatabase Design” was also reviewed.

Third, the H-GAC South East Texas Addressing and Referencing Map (StarMap), which is currently maintained by Robert and his team, was updated in order to test the newly formed 9-1-1 database schema.  By January 2008, the schema was adopted by both the GDC and the 9-1-1 coordinators and work was done internally to finalize the schema for the StarMap. The 9-1-1 county data was also transferred to the new format in the H-GAC regional geodatabase.

Next was the consideration and adoption of the type and form of replication that was needed.  There are two forms of replication that various entities have the option to use.  One is Database Management System (DBMS) replication which involves database synchronization between either SQL Server or Oracle databases directly using the DBMS replication mechanisms.  The other replication format is ArcGIS Geodatabase replication which involves using a GIS Server (which may utilize Oracle or SQL server) to replicate data to other GIS applications over the Internet. 

Before Robert and Rebecca had arrived, H-GAC had experimented with other types of GIS replication within their GIS but, due to software glitches, H-GAC was never able to implement replication with more than a couple of local entities. 

Robert and the GIS team next reviewed the various forms of replication and chose ArcGIS Server replication in early 2008. This decision was based on the fact that this functionality was freely bundled within the current software that H-GAC already owned and also because ArcGIS Server replication would allow the GIS at H-GAC to synchronize data updates to an entity’s existing ESRI GIS application. 

In many instances, 9-1-1 agencies may not have had the funds or resources to manage an enterprise database such as Oracle or SQL Server but all the partnering rural counties were already using existing ESRI ArcGIS applications that could be used for replication.  In January 2009, Robert and his group loaded the first set of 9-1-1 county data sets into the revised regional database schema geodatabase to begin preparation for the initial replication testing with Colorado County. Around September 2009, the initial replication was started then other counties followed.  Since 2009, more and more counties started coming online with replication and now 6 rural 9-1-1 counties are online replicating with the last 2 hopefully coming online in the next year.

To top it off, H-GAC’s Data Services GIS is replicating portions of the entire regional data set with their 23 public safety answering points (PSAP) that service the region.

For those who may not know what a PSAP is, it is simply a call center responsible for answering calls to an emergency telephone number for police, fire, and EMS. These PSAP personnel then take the calls and dispatch them to the various agencies responsible for the geographic area from which the call originated.  In the past, these GIS maps were updated manually by hand but now with GIS replication, the layers are now updated more speedily and automatically.

In conclusion, H-GAC’s mission is to serve as the instrument of local government cooperation by promoting the region’s orderly development and the safety and welfare of its citizenry.  One way it plans to accomplish this is through making for a more accurate and efficient GIS that will improve how emergency services respond to crisis whether they by fire, police or EMS.

For more information on H-GAC, see

- People, Places & Things/ (via H-GAC, 8/2/12)


Show: Newest | Oldest

Post a Comment

Log in or sign up to comment

9-1-1 Magazine is a Sponsor of the California Mobile Command Center Rally

Send mail to with questions or comments about this portal.

© 2010-2017 9-1-1 MAGAZINE and The content of this portal is the property of 9-1-1 MAGAZINE and  We encourage government public-safety agencies to share any content with their staff, however, all others must not duplicate or modify any content without prior written consent of 9-1-1 MAGAZINE. Email for permissions. For more information, read the Terms of Service. Continued access of this portal and system implies consent to the above statements and those maintained on the Terms of Service.

Powered by Solata

MCM Consulting Yellow Submarine Marketing

 Team Rennick