2015 Digital Orthophotography

2015_Ortho_AOI-(1).jpgIn 2015, the North Central Texas Council of Governments facilitated the cooperative purchase of 4-band, 3-inch and 6-inch resolution digital aerial photography (orthos) for over 7,500 square miles of the NCTCOG region including all of Collin, Dallas, Denton, Tarrant and Rockwall counties and portions of Hunt, Kaufman, Ellis, Johnson, Hood, Navarro, Parker, Palo Pinto and Wise counties. 
The contractor for this project was Woolpert.   The orthos were collected in January and February 2015 (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:

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

Specifications

The coverage area for 2015 includes Dallas, Fort Worth, and surrounding urban and rural counties totaling 7,523 square miles, of which 448 square miles is 3” resolution.   Four areas of 6” 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, totaling approximately 24 square miles. 

The flight design achieved a nominal ground-pixel resolution sufficient for developing 3” and  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” = 50 and 1"=100' scale mapping. 

3-inch Flight Specifications

Camera Microsoft UltraCAM Eagle
Altitude of Capture 9,900 Feet AGL
Focal Length 100mm in non-restricted airspace and 210mm in restricted airspace
Capture Period January 15, 2015 – February 8, 2015               
Ground Conditions  Leaf off; free from snow, haze, fog, or dust;  streams within normal banks
Atmospheric Moisture Less than 5% cloud cover
Sun Angle Greater than 30%
Forward Overlap 60%
Sidelap 30%
Coordinate System Texas State Plane, North Central Zone
Horizontal Datum NA 83
Vertical Datum NAVD88
Units US Survey Feet
Format TIFF, MrSID Generations 2 and 4
 

 

6-inch Flight Specifications

 
Camera Microsoft Ultra CAM Eagle
Altitude of Capture 9,500 Feet AGL
Focal Length 100mm
Capture Period January 15, 2015 – February 8, 2015
Ground Conditions  Leaf off; free from snow, haze, fog, or dust;  streams within normal banks
Atmospheric Moisture Less than 5% cloud cover
Sun Angle Greater than 30%
Forward Overlap 60% (80% for True Ortho areas)
Sidelap 30% (60% for True Ortho areas)
Coordinate System Texas State Plane, North Central Zone
Horizontal Datum NAD83
Vertical Datum NAVD88
Units US Survey Feet
Format TIFF, MrSID Generations 2 and 4
  

More information on the 2015 project can be found in the Project Plan and project level metadata:

3-inch Orthophotography
6-inch Orthophotography
True Orthophotography

For questions about the 2015 digital aerial photography project, contact Shelley Broyles.