Our aerial photo interpretation experts have provided testimony in both State and Federal Courts in the areas of aerial photo interpretation and photogrammetry. Our testimony often includes the areas of surface water hydrology and agronomy as it relates to the photo interpretation of surface drainage features and vegetation features.
Our experts have studied over 1000 sites in the United States, Australia, Canada, Jamaica, Puerto Rico, and the U.S. Virgin Islands. These projects have included historical aerial photography based hazardous waste site investigations, surface mine inspections and permitting, environmental audits, accident site investigations, annual site documentation using aerial photography, video, and thermal imagery, contour mapping of plant sites, stock pile volume determinations, geographic information systems and coastal zone erosion studies.
Historical Aerial Photographs
Most industrialized areas in the United States have been photographed from the air at regular intervals since the 1940s. Because these aerial photographs illustrate when, where, and what activities occurred at a site, we can use them to identify or exclude potentially responsible parties at sites where environmental damage has occurred.
When we conduct an aerial photographic study, we research our extensive aerial photo archive as well as the collections of government and private providers for aerial imagery of your site. When available, we obtain the aerial photos in stereoscopic format. We can also obtain historical maps and climatological data if needed.
Stereoscopic Aerial Photos
During aerial photo missions, the camera, which is mounted on the bottom of the airplane, shoots one frame after another as the airplane moves across its flight line. Because these consecutive frames overlap, each frame includes an area covered by its neighboring frames. We import these frames into our soft copy workstations. When these aerial photographs of the same area taken at slightly different angles are viewed together, the image appears in stereo (3-D).
Geo-Registration of Aerial Photographs
We electronically geo-register the different frames of aerial photography to a coordinate system. Each stereo model (overlapping frames) shows the features within your site in their true geographic position. This allows us to determine the position of significant historical features relative to the features at the site area today, to generate terrain models, to make height, depth, and distance measurements; and to calculate area and volume. (View 3-D Model of Our Office Building)
As we identify features in the stereo models, we map them on the screen. These features may include buildings, drainage channels, drums, equipment, fill, lagoons, piles, pits, and tanks. As we progress through the different historical dates of photography, we document changes in the condition of vegetation, when contamination is seen, when structures were constructed or dismantled, and what activities occurred upstream or adjacent to the environmentally impacted area.
We digitally tie the overlapping frames of photography for each date together to produce a seamless photo mosaic. This photo mosaic is called an orthophoto. An orthophoto is equivalent to a map of the same scale. Because each historical date of photography is registered to a coordinate system, each orthophoto produced of a date registers to all the other historical aerial photos acquired. When the orthophotos are viewed in sequence, the orthophotos provide a time lapse perspective of your site.
Importing Orthophotos into a Geographic Information System (GIS)
We import the orthophotos for each date and their corresponding vector data (the points, lines and polygons generated by mapping the features) into ArcGIS, a geographic information system (GIS). The GIS allows us to toggle back and forth between dates, which is useful for change detection analysis. We can also overlay the images with plaintiff location data and parcel data.
Our experts use a computer projection system in court. The aerial images can be shown in a time lapse to show the development of the site relevant to significant historical features. We can toggle back and forth between dates, turn vector layers on and off, and zoom in out to different features.
Our trial booklets include a series of cropped, scaled and interpreted images for each date of aerial photography. The trial booklet may also include a series of anaglyphs for each date. The anaglyphs, when viewed with special glasses, show the site area in 3-D.
Large Format Plots
We can produce large format plots of your site for courtroom displays.
For Further Information about Our Expert Witness Services
Call us now at 225.767.5725 or email us at email@example.com to discuss your project.