Copyright GeoComm, Inc. All rights reserved.
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
“ACOG has many vendors for technical and non-technical projects. Our business relationship
with GeoComm is one of the most positive we have ever experienced. GeoComm is very
responsive to both routine requests as well as special requests for information or technical
changes. Because of our experience with GeoComm we have contracted with them for two
major projects: developing a four-county regional data set and providing GeoLynx 9-1-1 to all 22
PSAPs in our jurisdiction. In addition, we have long-term GIS data and software maintenance
contracts."
- Steve Willoughby, Association of Central Oklahoma Governments Division Director
9-1-1 Association of Central Oklahoma
Governments (ACOG): Public Safety GIS Data
Distribution
GIS
Articles & Case Studies