Production of a Sustained, Statewide Orthophoto Base for Tennessee

Kim McDonough, GISP
Tennessee Department of Transportation
Nashville, TN

Several states have embarked on statewide imagery projects for the purpose of creating a single, consistent reference base for everything from 911 to parcel mapping to economic development.

Tennessee has also embarked on a statewide ortho project, but from a different angle. The Department of Transportation (TDOT) and the Department of Finance and Administration (F&A) originally conducted two different aerial photography programs. F&A collected high resolution, countywide digital ortho photos while TDOT obtained lower resolution film based regional aerial photos. These two departments have now combined their programs to create an ongoing program of high resolution color orthophotography for the entire state. This required TDOT to completely overhaul their camera and processes, which has been a very substantial investment for this agency. However, TDOT not has a much higher quality product for its use and the state has a consistent product that is updated every four years. This imagery is now used by all state agencies and local governments as well.

It was a challenge to merge the two programs and adjustments are still needed. TDOT has found that hardware and software really isn’t geared toward this sort of very large scale, ongoing process. Federal programs are extremely siloed and also not well coordinated to support this type of multi agency coordination. We have also been challenged in finding an accurate DTM for use across the state. But despite the challenges, Tennessee stands to save substantial dollars while producing a common base that was impractical and unavailable less than 10 years ago.