Topo Survey Flight Topo Ortho Map Acc

The classical definition of orthophoto is the conversion of a central projection (the photo) to an orthognal or parallel projection (the plane). Orthophoto images are derived from conventional vertical aerial photography by rectifying the distortion caused by ground relief and camera tilt.

P.T.I. uses the most recent method of orthophotos production comes from scanned images which are rectified via the photogrammetri softcopy workstation, where a scaled Digital Terrain Model (DTM) is created to establish precise positioning of individual pixels. The final rectification is completed by draping the entire scanned image over the DTM.

The resulting orthophoto is delivered in hardcopy or electronic formats, the resolution is determined by pixel size, a smaller the pixel will generate a larger file:

 Pixel Resolution

 File Size in MB

 Sheet size

1.0 foot 

 12.5 MB


 0.5 foot

 50.5 MB


P.T.I. can provide orthophoto data at additional cost for any part or all of your project area. Due to the vast volumes of data required for orthophotos, care must be taken to prepare storage to accomodate it.


103 Washington Street, Po. Box 349 Weymouth, MA 02188 Tel:: 781-335-7229 Email: