Sidwell's technicians' knowledge of principles and practices in photogrammetry is complemented with the use of all industry standard equipment including Airborne Global Positioning System (AGPS), flight management software, softcopy photogrammetry systems and stereoplotters.
Unlike our competitors, the entire orthophotography production process takes place at our production facility in St. Charles, Illinois. Our precision aerial camera is tested and calibrated by the U.S. Geological Survey. At our facility, technicians use a precision photogrammetric scanner to scan aerial film, ground control is obtained and analytical aerotriangulation is performed - acting as a conduit between ground control and the aerial photography. Through stereoscopic measurement and autocorrelation processing of the photography, a digital elevation model (DEM) is produced which results in a grid of points defining the shape of the earth's surface. The image scans, ground control and DEM data are combined via software to "wrap" the perspective photo onto the DEM data. Once the image is re-sampled, software is used to blend the images together to form a continuous, seamless image. The resulting orthographically correct imagery can be provided digitally for viewing at various scales or plotting on film or paper at a scale suitable for your project.
Our dedicated team continues to provide products and services that exceed client expectations. Our success lies in the continued education of our staff, technological advances made in the industry and more than 50 years of experience in aerial photography and photogrammetric services.