Reso 2001-375 - Laserfiche WebLink

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All the targets shall be located with GPS instruments, tied-in to local NGS control monuments. All target locations shall be tri-dimensional. Information of target locations will be utilized in the stereoscopic photograph processing. 1.1.1 Coordination The Surveyors will meet and coordinate with the Photogrammetrist the placement of the individual targets. These preliminary locations will be marked on a map for field placement. Once the map is completed, the Professional Land Surveyor (PLS) will meet with the crew in the field and verify that the preliminary target locations are suitable. If a location is not suitable for target placement, then a new location will be chosen and marked on the map. Once targets have been set, located and the coordinates accepted and approved by the PLS, they will be forwarded to the Photogrammetrist to begin rectification of the aerial data. When the Photogrammetrist has completed his work, an ASCII file containing the X, Y, Z, values for all points and a CADD file of line work will be provided to the PLS for creation of the Digital Terrain Model (DTM). 1.1.2 Setting Target Locations Once all target locations have been checked and approved, the field crew will commence with the placement of the individual targets. A P.K. nail and washer will be set at all target centers placed on hard surfaces. For targets set on ground, either an SOd spike or iron rod with cap will be set for the center. 1.1.3 Placement of Targets Once all target centers are placed, targets will either be painted (a color contrasting with the surface, usually white or black), or a cloth target placed. All targets will be 4' x 4' crosses, unless requested otherwise by the Photogrammetrist. Once al targets have been properly placed and approved by both the PLS and the Photogrammetrist, location of the aerial targets will commence. 1.1.4 Target Locations and Coordinates Targets will be located using Global Positioning Satellite (GPS) equipment utilizing Rapid Static methods. Thorough reconnaissance and planning will be used to insure precise, accurate results with a minimum of effort. At least 2 dual frequency receivers will be placed on known control points with a published accuracy of Second order Class I or greater. Each target will be observed on it's center point twice, for at least 10 minutes with double occupations planned for .010_. 4. ond _'no.