2013 Digital Orthophotography

2013coverage.jpgIn 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:

6-inch Resolution  Sample (coming soon)
TIFF orthophotography grid

Specifications

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
 

More information on the 2013 project,  view the project level metadata.

For questions about the 2013 digital aerial photography, contact Shelley Broyles