Henry County, Tennessee 911
Henry County 911 Dispatch
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GIS Mapping

Click Below for Henry County 911 online interactive map

Henry County installed a new GIS mapping system in October of 2007. The system allows the callers location to be displayed on the map.

GIS(Geographical Information System) is new to the 911 arena. The need to locate cellular calls with the new Phase II of wireless 911 technology has brought GIS to the forefront. Henry County was one of the first counties to have it’s own mapping system back in the early 1990’s. That system was based on Autocad and the streets had to be hand drawn and were not to scale. With the new GIS system, aerial photographs of the county allow for structures and streets to be as precise as possible.

The GIS software called “Geo911”, and the software places an icon at the exact location of the call. If it is a 911 call from a landline phone, the location is based on the street address of the caller. If the call is a cellular call, the location is based on the X-Y coordinates supplied by the wireless carrier with the 911 call. The dispatcher sees a one mile square block of all the addresses and streets surrounding the call. The dispatcher can zoom in or out or pan across the map as needed to zero in on the caller’s location.

The GIS system contains over twenty layers of data displaying not only streets and house numbers, but such things as fire hydrants, Fire Department boundaries, driveways, lakes, ponds, and surrounding county roads to name just a few.

The aerial photography in the GIS system is probably one of the most used features. The photographs taken in 2009 allow you to see the actual structures and terrain with impressive clarity. This gives the feeling to the dispatcher of flying in a helicopter and being able to see everything from the air.

The maintenance of the GIS system is done by the 911 Office. With any database, the information must be kept current to be effective. The 911 Office uses ESRI archives to maintain the data. There are different agencies or departments that the data is provided to. Every city and county department has the opportunity to use the GIS system.

The Henry County 911 Office also provides a software product called MapSync to the Emergency Agencies in which the GIS data is loaded.

     
Our aerial photography called "Raster Data' was provided by the Tennessee Base Mapping program which is a state agency. As you can see the clarity is remarkable and you can actually count the cars on the Henry County High School's Campus. The precise aerial photography allows dispatchers to actually see how driveways run to houses and outside layouts of the houses themselves. Our GIS system shows not only all house numbers but fire hydrants, and the actual parcel boundaries of each plot of land.
     
Our GIS and 911 systems are tied together. The map automatically locates the 911 call and places a red circle icon for easy view by the dispatcher. Surrounding house numbers and streets are displayed which allows emergency responders to easily locate the emergency.