Providence, Kentucky, Digs Out From Tornado Damage With the Help of GIS
On Sunday, April 28, 2002, at 3:00 a.m., an F3 (on a scale of F0-F5 with F5 being the most violent) tornado hit the small town of Providence, Kentucky, damaging 378 structures in a town of approximately 2,500 parcels. More than 150 houses were destroyed in this natural disaster.
On Monday morning, the Webster County Property Valuation Administrator's (PVA) Office contacted the Kentucky Revenue Cabinet (KRC) to inform it of the disaster and request assistance.
The PVA uses GIS to maintain maps of parcel lines to identify property ownership with tables of information and characteristics of each parcel and road centerlines to assist 911 in addressing, and it uses customized printouts to show price per square foot of residential housing or price per acre for farmland to assist in assessment of properties geographically.
In 2000, Webster County received a technology grant under Commissioner of Revenue Vince Lang and purchased computer equipment and ArcView software under a state bid procurement to begin digitizing parcels.
Old maps were scanned in by the Technical Support staff and registered to MrSID aerial photos using the ArcView Image Analysis extension. This was a relatively simple task that required a project be set up in ArcView with the base layer being the desired output data; then the scanned images were moved and resized by clicking on two points that should be identical. The software yielded a distortion factor to allow the user to see what level of distortion may be occurring between registered control points.
Technical Support then trained the Webster County staff on digitizing parcels from the overlay and other information tables on parcels. Digitizing parcels is done by registering old map information, then digitizing the lines as they appear on the registered image. When that image is removed, the lines should fit on the newer image. This required learning how to set up projects, add image layers, add feature layers, set properties for points and lines such as color and size, and use draw functions.
Webster County PVA was also assisted by Bill Smith and Philip Meyer of the Green River Area Development District who GPS located road centerlines and provided shapefiles of county, city, and other data that they had digitized or acquired from other sources.
Taking the Bull by the Horns
With this wealth of information available, Commissioner Lang sent KRC GIS Coordinator Mike Tackett to ground zero to begin the assessment of damage. Tackett obtained the most current shapefiles from PVA to begin this project. Entering an area that had been secured by National Guardsmen, Tackett received assistance from the nearby Crittenden County Road Department. In a little more than one day, they were able to GPS locate each damaged structure, enter information into a table, and hyperlink a photograph. This enabled PVA to locate each damaged structure for reassessment and estimate the damage that had occurred.
"GIS is essential for disaster projects such as the Webster County tornado project," says Tackett. "Instead of the damage assessment work taking months, with GPS and GIS the damage can be assessed in days or weeks. The GPS data was collected and photographs were taken in less than two days with all the processing and hot linking of photographs done at night in Webster County. And with just a little extra work, PVA assessment data was attached to show an estimated amount of property damage."
The Technical Support staff took this information and printed maps for Webster County PVA, Municipal Office, and county officials. The Municipal Office used these maps to track turnoffs and turn-ons of electric, gas, and water and debris removal.
"ArcView helped us assemble the data and print maps for the Providence Fire Department," says Tackett. "These maps were used to mark any property missed in the initial survey and keep track of gas valve or electricity turnoff for the Fire Department."
The maps and data were provided to the U.S. Federal Emergency Management Agency (FEMA), which then declared the area a federal disaster eligible for federal assistance for cleanup and rebuilding. Since then, many individuals are either in new homes or at some stage of repair or rebuilding of their damaged homes.
Although GIS has been used by other agencies in Kentucky over the past 15 to 20 years, GIS is relatively new to the Commonwealth of Kentucky Revenue Cabinet, which has made great strides in digitizing parcels in many Kentucky counties with the assistance of State Valuation's Technical Support Branch--Ron Johnson, cartography branch manager; Patti Royster, program coordinator; Mike Tackett, GIS coordinator; and Patti Hall, David Thornton, and B. David Wilson, geoprocessing specialists.
To see the path of the tornado with damaged structure points, visit www.webstercountypva.com and click on Property Maps. A map of this county has been set up by Kent Anness of the Kentucky Infrastructure Authority, which has provided support and assisted with the Webster County GIS. For more information on Kentucky GIS, visit kygeonet.state.ky.us.