2013 Digital Orthophotography
In 2013, the North Central Texas Council of Governments facilitated the cooperative purchase of 4-band, 6-inch resolution digital orthophotography (orthos) for 5,777 square miles of the NCTCOG region including all of Collin, Dallas, Denton, Tarrant and Rockwall counties and portions of Hunt, Kaufman, Ellis, Johnson, Hood, Parker and Wise counties.
The contractor for this project was Woolpert. The orthos were collected in January and February 2013 (leaf-off) and are available for purchase via the DFWMaps Marketplace according to the following price schedule.
Georeferenced TIFF images are sold in 3,000' x 2,000' tiles, or 0.215 square miles. Sample images and a shapefile of the tile structure may be downloaded below:
The coverage area for 2013 includes Dallas, Fort Worth, and surrounding urban and rural counties totaling 5,777 square miles. Four areas of true orthoimagery were produced over the central business districts of Dallas and Fort Worth, as well as the I-635/US-75 intersection, and the Dallas North Tollway corridor from I-635 to Keller Springs Parkway, all totaling approximately 24 sq. miles.
The flight design achieved a nominal ground-pixel resolution sufficient for developing a 6" pixel orthophotography without oversampling. It was also designed with sufficient forward overlap and strip side laps to ensure total project area coverage. The final aerial photography meets The American Society of Photogrammetry and Remote Sensing (ASPRS) Class I standard for 1"=100' scale mapping.
|Altitude of Capture||Approx. 4,774-8,500' above ground level|
|Focal Length||120 mm (4.72")|
|Imagery Scale||Minimum: 1"= 1764' (Photo scale 1:21167)
Maximum: 1" = 2129' (Photo scale 1:25552) – Main block DFW restricted airspace
|Capture Period||January 20 - February 23, 2013|
|Conditions||Leaf off, cloud free, 30 degree minimum sun angle|
|Forward Overlap||60% (80% for True Ortho areas)|
|Sidelap||30% (80% for True Ortho areas)|
|Coordinate System||Texas State Plane, North Central Zone|
|Horizontal Datum||NAD 83|
|Units||US Survey Feet|
|Format||TIFF, MrSID Generations 2 and 4|