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each point. The second occupation will utilize a different satellite configuration and wherever possible, different control points from the first observation. All vectors will be observed and processed, first through an unconstrained adjustment, and then constrained to the original control points. This will be performed twice. The first time through the Pinnacle processing software provided by TopconlJavad, the second time through Hector the Vector software developed by the University of Maine, and used by the Florida DOT. The results will be compared as a Quality Control I Quality Assurance measure. Any target locations that exceed the standards set forth for this type of work will be re-observed and reprocessed to insure reliability of coordinate data. Once all work has been processed and approved, a second overall Network adjustment will be made including all target locations and control points utilized in the locations. A series of three wire bench runs will be made from recovered benchmarks, through each target to verify the elevation values generated by GPS methods. This step is extremely critical. Because GPS derived elevations are subject to greater outside influences and error propagation than the horizontal, X, Y coordinates. These vertical values will be compared to the GPS derived values. If there is an unacceptable level of inconsistency between the two sets of elevations, the horizontal adjustment will be rerun based on the new elevations. All horizontal coordinates will be State plane coordinates based on the 1983/90 adjustment for the Florida East Zone. All vertical values will be based on 1929 N.G.V.D. 1.1.5 Digital Terrain Model The Digital Terrain model or DTM will be created based on the points and line work files supplied by the Photogrammetrist. A Least Squares Analysis will be run against the DTM and the points used to test and verify the quality of the DTM compared to the points comprising it. Then this DTM will be checked against spot elevations and 1 or cross sections taken in the field to verify the validity of the model to the existing ground surface. If any data does not conform to the Florida Minimum Technical Standards, or the National Map Accuracy Standards as set forth for Aerial Photogrammetry, additional field work will be performed to locate and the source of the unacceptable data, correct it, and re-compute and retest the DTM. 1.1.6 Field Verification of Digitized Topography The digital topographic files supplied by the Photogrammetrist will be plotted out to facilitate field verification. This essential step in the process is performed by Beiswenger, Hoch and Associates, Inc.