9-1-1 Association of Central Oklahoma Governments (ACOG): Public Safety GIS Data Distribution

Business situation

The 9-1-1 Association of Central Oklahoma Governments (ACOG) and GeoComm needed to synchronize GIS data updates made by both of their GIS departments to the ACOG regional data set. In addition, the most current GIS data set needed to be distributed to all 22 regional PSAPs covering an area of 3,000 square miles.

Determining the regional data set synchronization maintenance process, ACOG and GeoComm had to consider two main factors. ACOG and GeoComm use two different Environmental Systems Research Institute (ESRI) GIS enterprise environments. And both GIS staffs have multiple GIS data editors updating the same regional GIS data set daily from two locations 850 miles apart. The maintenance process also had to consider the most efficient way to schedule and deliver GIS data updates to all 22 PSAPs.

Technical situation

Multiple GIS data editors view, edit, and maintain 9-1-1 ACOG’s regional GIS data set in an enterprise geodatabase system using ESRI’s ArcInfo Spatial Database Engine (ArcSDE) technology. ArcSDE technology is installed and running on two server types: Oracle and SQL servers. Using ArcSDE technology, both GIS staffs edit the regional GIS data set daily in both offices. These simultaneous, daily updates to the regional GIS data set require the GIS data editors to post map updates to a master regional data set located at each individual office. Then the two data sets are synchronized so all GIS data editors are viewing the same map data at both locations. This also remedies 9-1-1 ACOG’s requirement in their disaster recovery plan for geographically diverse locations for their regional GIS data set.

In addition to the daily maintenance of the regional GIS data set, the 22 PSAPs using the data in a GIS dispatch mapping application require delivery of updated map data on a scheduled basis. It was important to 9-1-1 ACOG that someone did not need to provide manual GIS data updates to all 22 PSAPs. This process could not interrupt service or require a long upload time due to large file sizes being pushed and pulled across multiple networks.

GIS Data Synchronization Using Geodatabase Replication

Geodatabase replication is a data distribution method available in ESRI’s ArcGIS. There are three primary types of geodatabase replication: check out/check in replication, one-way replication, and two-way replication. To determine the distribution method to use, GeoComm considered:

Multiple data editors in two disconnected environments
Versioned data
The ability to transfer changes multiple times
Two database management systems: SQL Server DBMS and Oracle DBMS

With these considerations in mind, ACOG and GeoComm selected two-way replication. This replication method was selected because it allowed GIS data changes to be synced multiple times from one data set to the other in a disconnected environment, worked well with versioned data, allowed transfer of changes multiple times, and worked with the two different database management systems, therefore, appealing to all of the technical considerations.

Setting up two-way replication required GeoComm and ACOG to define what data to replicate from a source ArcSDE geodatabase. After selecting the data to replicate, GeoComm used ESRI’s distributed geodatabase toolbar to copy data from a source ArcSDE geodatabase at GeoComm to a target geodatabase at ACOG.

Due to the disconnected environment, GeoComm created the replica to an XML document. The XML document was then imported into a relative geodatabase at ACOG. Once this import was complete the two master regional data sets are configured and maintained as a parent geodatabase and a child geodatabase.

Using the distributed geodatabase toolbar in ArcGIS, GeoComm ensures both regional GIS data sets are synchronized on a scheduled basis. Using the distributed geodatabase tool, GeoComm builds a file, called a message. The message contains only changes made to the parent geodatabase since the last synchronization. The message is exchanged with the updated child geodatabase at 9-1-1 ACOG over a secured Internet connection. The process is completed again, only this time, the message is created from the 9-1-1 ACOG child geodatabase and change only data is sent to the GeoComm parent geodatabase.

After the messages are exchanged, GeoComm and 9-1-1 ACOG data editors are able to see the GIS data updated by each office.

Using two-way replication effectively synchronizes the GIS data, while avoiding long periods of downtime where data editors at GeoComm and 9-1-1 ACOG cannot access the GIS data.

PSAP GIS Distribution Using GeoLynx Sync

Distributing map data maintained by GeoComm and 9-1-1 ACOG on a regular basis is important to 9-1-1 ACOG’s public safety services. Since 9-1-1 ACOG has the foresight to connect all 22 PSAPs on the same secure network, GeoLynx Sync can be easily used to facilitate scheduled updates to all 22 PSAPs. GeoLynx Sync is a tool for automatically distributing GIS data and software configuration and application updates to PSAP workstations. GeoLynx Sync eliminates the task of traveling to many workstations and then downloading the files or copying them from CDs to each workstation.

GeoLynx Sync is setup on a local server in Oklahoma City to facilitate distribution of GIS updates to 9-1-1 ACOG’s 22 PSAPs. From this server, GeoComm technical support analysts are able to test, package, and schedule GIS updates to each PSAP. GeoLynx Sync allows complete control over what day and what time updates occur. At a specified day and time, GeoLynx Sync replicates the GIS update package to each dedicated workstations at a particular PSAP.

After the last scheduled GIS updates are complete, GeoComm technical support analysts connect to GeoLynx Sync using a secure Internet connection to verify that all workstations have been updated. The technical support analyst runs an additional utility that acquires information from all 22 PSAPs pertaining to wireline and wireless Phase I calls that did not plot on the GeoLynx 9-1-1 map. The information is dispersed to 9-1-1 ACOG and GeoComm data editors for review and resolution to ensure ongoing location accuracy for emergency response.

Benefits

Eliminates sending entire regional data set between GeoComm and 9-1-1 ACOG

Maximizes server database technology

Leverages ESRI technology by sharing data modifications between two server types: Oracle and SQL

Streamlines workflow allowing multiple editors in different locations across the country to maintain the same data set

Increases productivity by allowing all editors access to the data set at all times and including their updates

Products and services used by GeoComm and 9-1-1 ACOG:

Oracle DBMS
SQL Server 2005 DBMS
ArcGIS Server 9.2 with ArcSDE Technology
ArcGIS desktop
GIS data maintenance services provided by GeoComm
GeoLynx DMS for GIS data maintenance
GeoLynx Sync
GeoLynx 9-1-1

Partnership profile

The 9-1-1 Association of Central Oklahoma Governments (9-1-1 ACOG), an operational arm of ACOG, was formed to implement and manage the enhanced 9-1-1 emergency telephone number and system for suburban communities in the Oklahoma City metropolitan area. In addition, a 9-1-1 Technical Committee involving representatives of the public safety agencies in the system was created to facilitate exchange of information, concerns and improvements in the system’s efficiency.

GeoComm worked with 9-1-1 ACOG to develop regionwide GIS data standards. Then GeoComm developed a comprehensive regional GIS data set meeting those standards to serve 22 PSAPs in the greater Oklahoma City area.