Aerial Photography
To achieve accurate measurements it is necessary to use an extremely precise camera and lens. The camera we use is a Leica (formally Wild) RC30 with FMC or forward motion compensation. This camera uses negative roll film with a nominal image size of 9" X 9" has a focal length of 153mm (+/-6") and has a current USGS calibration.

The lens is state of the art for both accuracy and image resolution. To enhance the quality of the image this camera employs forward motion compensation, which virtually eliminates image blur resulting from the forward motion of the aircraft.

GPS is used for navigation to the exposure station. The camera is also fitted with Airborne GPS which provides the precise coordinates of the camera at the time of exposure. These coordinates help to reduce the overall number of ground points required to control a specific area. For improved accuracy, and at the same time further reduce the number of control points required, this camera system is equipped with the POS/AV system by Applanix. The system consists of an inertial measurement unit which works in conjunction with the Airborne GPS. The system not only records the coordinates of the camera but the pitch and yaw of the aircraft. The end result is improved vertical accuracy, as well as the orientation parameters of the stereo model

Photogrammetry
Delta Geomatics uses "SoftCopy Workstations" for all of our mapping related tasks. "SoftCopy" employs high resolution high accuracy scans from the original negative or diapositive. The images are scanned at 15 micron resolution which is the equivalent of 1696 dpi.The images are imported into the workstation and by using the "stereo emitter" on top of the monitor, plus special glasses, our operators are able to view the images in stereo. With the assistance of real time analytical aerial triangulation, coupled with sufficient survey control, we are able to work with a continuous 3D stereo model which covers the entire project at one time.

Apart from the obvious advantage of having the entire project at our fingertips, "SoftCopy" also superimposes the 3D vector data on the image in it's proper "X,Y,and Z" location. This feature provides the operator with a continuous check on the quality of his work at all times. Contours are generated from discrete points and 3D breaklines. Both the breaklines and the contours can also be superimposed onto the image. If more information is required it is immediately obvious to the operator and he can add that data in realtime.

As well as the conventional map data we also provide a "3D surface" file which the client can use to generate his own contours if desired.

Digital Orthophoto
Delta Geomatics added digital orthophotos to its product line in 1995. Most people relate to aerial photographs more easily than line drawings or maps, but conventional aerial photos are only to scale at one given ground elevation and are not suitable for accurate measurements. Orthophotos, on the other hand, are corrected for scale differences, height displacements due to relief, plus camera tips and tilts. The final product is virtually as accurate as a map at the same scale. Orthophotos are very popular when combined with the property boundary as a base for ALTA surveys required by lending institutions.

The orthophoto can also be combined with a contour layer, or underground "as-builts", such as sprinkler systems or sewer and water lines. The orthophoto can be provided in hard copy on either paper or mylar, but the most valuable deliverable is a geo-referenced digital image which can be viewed and manipulated on a graphics work station, or GIS platform in conjunction with vector overlays.

This technology continues to attract new users, and is becoming especially popular with the GIS community, once again proving the axiom " a picture is worth a thousand words"

Consulting
Delta Geomatics provides accurate, precise data, on time, and for a fair price. If you need help planning your project or merely want to explore your alternatives, contact us.
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