Digital Orthophoto Mapping

LaFave, White & McGivern, L.S., P.C. is now able to offer digital orthophotography combining the accuracy of digital photogrammetry with the digital image of aerial photography providing an abundance of remote sensed information. Digital overlays such as natural resources, property ownership, zoning, utilities and E-911 addresses can now be overlaid to the geographically accurate photo image This digital ortho-corrected imagery allows the user to place it within a Geographic Information System (GIS) on either a mainframe or stand alone work station.

• A digital orthophoto is a computer differentially rectified and scaled ortho image. In order to insure accuracy the aerial photography must be taken with a precision metric aerial mapping camera with forward image motion compensation. This camera lens is usually of six inch focal length and the camera must be calibrated by the U.S. Geological Survey.

• Digital orthophoto production is accomplished by scanning the photographic image in transparency or negative form at a predetermined Dots Per Inch (DPI) with a precision metric quality scanner which converts the photographic image into picture elements called pixels. Stereo-photogrammetrically captured digital terrain model X, Y & Z coordinates are then digitally related to the Pixel coordinates in a transformation. This transformation removes image displacement creating a digital ortho-image with greater geographic accuracy than is possible with standard analog ortho photography.

• Digital orthophotography provides to the GIS community a cost-effective and accurately scaled photomap upon which to construct a GIS database with speed and efficiency. The orthophoto is flexible in that it allows the GIS user ease in relating many non geographic features to the photo map base. It is also a unique tool for the planner and engineer.

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LaFave, White & McGivern, L.S., P.C. offers numerous digital photogrammetric services other than digital orthophotography. Please be sure to contact us for any of your requirements.