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Digital Orthoimagery Process Video

Planning for Success: Project Design

Digital orthoimagery is a seamless aerial image of the Earth’s surface. Beneath a digital orthoimage lies a three-dimensional surface model that accurately depicts the shape and form of the terrain. The imagery is measured against known points on the Earth that are verified by GPS to ensure the imagery meets accuracy requirements.

Surdex carefully designs each project with the required survey control, the most suitable sensor and aircraft, and the optimal flying height to ensure optimal image resolution, mapping accuracy and collection efficiency. Design elements include:

  • Terrain (farmland, urban, coastal, forest, etc.)
  • Resolution
  • Features desired to be captured, if the project includes mapping

Surdex will calculate the flying height required for the resolution (3”, 6”, or 12” GSD, for example), coupled with the control points dictated by the accuracy requirements. Then an aircraft / sensor combination is chosen which offers the best collection. Follow this link to see samples of orthoimagery at different resolutions.

A winning design provides for the most efficient approach, with the fewest flight lines necessary in order to achieve the desired accuracy and resolution.

RGB digital orthoimage
RGB digital orthoimage
Digital Ortho Image of Rural Farm Lands
Color infrared digital orthoimage

Image Processing

Following aerial acquisition, imagery is processed to orient it to known coordinates, refine the color balance, and remove irregularities. These processes provide clients with premium image quality guaranteed to meet your specifications.

To make continuous, seamless imagery, individual frames or strips of imagery are orthorectified and the color is balanced. This process includes:

  • Rectifying the imagery to known coordinates on the ground
  • Processing the imagery so the many separate images create a continuous, seamless image
  • Balancing color to ensure tonal quality and consistency throughout the project

The resulting digital imagery of surface features in their geometrically-corrected positions is free of the inaccuracies inherent in simple rectified photographs.

Once the orthoimagery is complete, any type of planimetric, topographic or cadastral data may be overlaid within a Geographic Information System (GIS) so that the user may quickly and easily find the information pertaining to an identifiable object.

Process Details

Pilot in Aircraft Cab Adjusting Controls


It is extremely important to keep aircraft crews acquiring imagery so data processing can begin and all projects can remain on schedule. Surdex takes these steps to keep the acquisition pipeline full:

  • The aircraft and sensor designated for a project are placed on the schedule
  • Weather is continuously monitored to ensure our resources are taking advantage of every window of opportunity for acquisition

Should weather become unsuitable in one region, crews are mobilized to other regions and other projects.

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