Comprehensive Environmental Inc. (CEI) is excited to offer services through our wholly owned subsidiary, EagleEye Aerobotics™ for Environmental and Engineering Services using small Unmanned Aerial Systems (sUAS) platforms, sometimes referred to as drones. This new service combines the use of customized real time imagery with CEI’s engineering and scientific expertise to provide superior access, timely site reviews and increased data precision. CEI’s EagleEye Aerobotics™ in-house pilots are certified by the Federal Aviation Administration (FAA) and fully insured for sUAS flights wherever you need them. Our pilots also are trained civil or environmental engineers or environmental scientists with the knowledge to help your projects succeed. As a fully certified small woman owned business (WBE), CEI’s EagleEye Aerobotics™ can help you meet your set aside needs.


How it Works

CEI’s pilots will confirm that they can legally fly a given site and that the weather forecast is favorable before beginning the survey.  Once airborne, the sUAS can collect both video footage and still photographic images of the area to be surveyed.  The survey area can be on the ground, or it can be of an above-ground structure such as a water tower or a building.  Spatial accuracy is double-checked and ensured by the use of several ground-control points or targets on the ground, visible in the sUAS photos, at known locations.

The photographic imagery is processed using state-of-the-art software that creates a two-dimensional mosaic of all the still photographs and reconstructs a detailed, three-dimensional model of the area or structure surveyed.  The software can then derive contours and a bare-earth surface from these products and perform accurate measurements of distance, area, and volume.  The repeatability of the pre-programmed sUAS flight path allows identical, repeated surveys of the same area over time, ideal for monitoring progress on construction sites, changing flow patterns in streams, or any other time-based variable.

For a more detailed description of how this technology works and a list of some completed projects, check out our white papers here!




  1. Flight Style

  2. Process

  3. Outputs



Video Inspection



As the sUAS flies its survey, it records real-time high-definition video footage of the study area or the structure to be inspected.  It will fly anywhere between 50 and 200 feet above ground and can approach within a few feet of the structure, if conditions allow.  The camera angle can point straight down, or in any direction between down and horizontal.  Upward-looking footage is not possible at this time.  Videos can be up to 20 minutes long and are generally produced in MP4 format.



When the sUAS flies a survey to recover straight downward-looking imagery, it records the images at a ground-sampling distance (resolution) of <1 inch to 2 inches depending on the flight altitude, which will usually be between 50 and 200 feet.  The post-processing software uses a combination of spatial fixes, matching tie points, and color matching to merge the photographs together seamlessly into a single orthophoto mosaic.  During the post-processing phase this mosaic can be further edited to sharpen specific areas, as needed.  The orthophoto mosaic is a 2D layer and is produced as a geographically referenced geotiff file, suitable for use in GIS or CAD programs or in Google Earth.


Right: A qualitative comparison of drone photography (upper half of image), with a resolution of about 1-inch with conventional aerial photography (lower half), normally 1-foot resolution at best.



Google Earth vs. Orthophoto



Google Earth images shown in the above left image in a stream modelling application, generally have a resolution of approximatley 1-meter (3.3 feet).  The sUAS data, with a 1-2 inch resolution, produce much more accurate measurements and calculations (above right).




Distance, Area & Volume Measurements

The data collected by the sUAS are geospatially accurate in three dimensions.  This means that we can measure lengths and distances not only "as the crow flies", but also taking into account the elevation differences between the end points.  Area calculations can be made for non-planar as well as planar areas.  Volume measurements are also made possible by the 3D nature of the data, so that stockpiles, excavations, embankment subsidence, sediment accumulations, or any other volumetric change can be accurately measured.


Left: The volume of a small depression in the 3D mesh, such as the settling pond in the upper image, is made by calculating the space under the blue plane representing the waterline (lower image).  Comparing with as-builts or repeating this calculation over subsequent surveys reveals the rate of infill.




The postprocessing sequence includes development of two 3D models from the spatial data collected by the sUAS.  First, a surface model is created which reconstructs the survey area exactly as the sUAS recorded it, including rooftops, vehicles, fence posts, etc.  The resolution of this surface is the same as the original imagery.  Then, if required, a bare-earth terrain model can be derived from the surface by removing the above-ground objects such as buildings and vehicles.  The resolution of this bare-earth model is five times the original ground sampling distance, or about 4.5 to 10 inches.  The 3D models are created as geographically referenced geotiff files and are GIS compatible.  Contours can be derived from either of these 3D models, at the resolution of the model they are made from, and can be exported in GIS shapefile format.




Above: The georeferenced orthophotos, 3D surfaces, and contours can be brought into ArcGIS and combined with other spatial data such as roads, water or sewer networks, etc.






The orthophoto mosaic can be imported into AutoCAD for use with all of your existing CAD data.  The postprocessing of the sUAS images also yields a 3D surface model and a 3D bare-earth terrain model, as described above, from which contours can be derived in .dxf format.  Additionally, a 3D textured mesh can also be exported in .dxf format for use in AutoCADD.  

Left: Orthophotos and contours from an sUAS survey, brought into AutoCAD Civil 3D can be combined with any other CAD data.



The very high resolution of the sUAS imagery in the context of GeoHecRas dramatically increases the accuracy of stream flow calculations.  They allow the development of more accurate and detailed stream cross-sections, bank elevations and configurations.  These cross-sections and elevations can be exported in shapefile format for use in GIS or AutoCADD.


Right: The 3D surfaces are compatible with GeoHecRas where they produce more detailed stream cross-sections (upper image) than is possible with satellite imagery (lower image).