Vertical aerial photography (sometimes called "satellite views", "aerial surveys", "orthophotos" or "orthomosaics") are photos taken straight-down (nadir) from either an aircraft or satellite. They are different than oblique aerial photography (sometimes called "bird's eye views"), which are photographs also taken from an aircraft, but at an angle. Vertical aerial photographs are generally not as aesthetically-pleasing as oblique aerial photographs, but are used as workable data, such as for aerial photo maps or to produce digital elevation models (DEMs).
Our goal with every photo mission is to understand each client's individual needs and capture the best imagery possible at a competitive price. No two photo missions are alike. We choose the best aerial platform and equipment for each project to minimize costs for our clients without sacrificing on quality. This flexibility and years of experience allow us to safely and legally photograph projects within restricted airspaces and hard-to-reach locations.
Custom, high-resolution aerial photo maps of entire cities that are comprised of hundreds or thousands of individual photographs merged into one detailed image
By analyzing hundreds or thousands of individual photographs, we can create very detailed orthophotos. Zoom-out to see the city boundaries or zoom-in to see individual structures, all in one file!
Each photo mission is prepared to the custom specifications discussed with the client in advance. Multiple flight lines are generated over the proposed site, designed for high overlap between flight lines and successive images. Ground control points (GCPs), if needed, are acquired for the project (we recommend using GCPs for all projects that will be used in a CAD/GIS environment), requiring an on-site visit with a dGPS.
The mission is flown with high-resolution cameras mounted in a vertical position, pointing straight down. Once the vertical images are all captured, we return to base and begin post-processing.
The images are geotagged and sent through an advanced Surface-From-Motion (SFM) system. This system analyzes each pixel in each individual image and is able to calculate very precise camera positioning using a variety of techniques, such as Automatic Aero-Triangulation (AAT) and Bundle Block Adjustment. Using this precise camera calibration data, a rough 3D point cloud is generated and the individual camera positions are displayed, allowing for a visual quality check of the project. If everything looks good, we introduce the previously-collected ground control point data to improve accuracy and densify the 3D point cloud, which is used to generate a DSM and the subsequent orthophoto.
We recommend having high-accuracy ground control points (GCPs) for all aerial mapping projects in order for the data sets to be as accurate as possible
Once a flight is completed, every pixel is processed by a specialized Surface-from-Motion (SFM) system. Advanced algorithms are able to calculate the elevation of each pixel by analyzing the movement of pixels in overlapping images
Specialty cameras can capture spectrums that the human eye can't see, such as Near-infrared (IR) that indicates plant stress and Far-IR which can show the differences in temperature (thermography)
The orthophoto (also called an "orthomosaic" or "aerial photo map") is an orthorectified mosaic of hundreds or thousands of images, which are processed together to create one seamless map
The digital elevation model (DEM) can be delivered as a digital surface model (DSM), which shows the elevations of every visible object or as a digital terrain model (DTM), which has every object that is not the ground filtered out
The 3D color point cloud is almost a blend of the orthophoto and DEM, with each point having a color value and an x, y, z coordinate
The 3D simplified texture mesh takes the points of the 3D color point cloud and fills the space between them with 2D polygons that are projected with textures, creating a less detailed, but also much smaller 3D model
Contour lines are generated from the DEM (either the DSM or DTM) and are a simplified, 2D way to illustrate elevation changes