SITE INFORMATION AND CORRESPONDENCE_1992

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• ' ' T feet below frost depth, and be a minimum of 500 feet apart. Witness posts shall be set within three feet of each monument. Horizontal control (1:10,000 and referenced to the NAD83) and vertical control (1:5,000 and referenced to the NAVD88) of "Third Order" or better shall be established for each of the monuments. All of the control points recovered and/or established at the site shall be plotted at the appropriate coordinate point on the topo sheets, and shall be identified by name or number, final adjusted coordinates, and final adjusted elevations. A tabulated list and a "Description Card" of all control points established or used shall be submitted in accordance with paragraph 8.6 of this scope. The Description Card shall show a sketch of each monument; its location relative to reference marks, buildings, roads, towers, and so forth; a written description telling how to locate the monument from a known point; the monuments name or number; and, the final adjusted coordinates and eleva- tions. 7.4.2 Topographic mapping. The topographic sheets of the area(s) indi- cated in Paragraph 7.0 shall be mapped at the scales and at the contour inter- vals detailed in paragraph 7.0. If the slope of the ground is such that dif- ficulty is encountered in showing the contours at one-foot intervals, the con- tours may be shown at two-foot intervals. All elevations taken in the field shall be shown on the topographic sheets and each five foot contour line shall be labeled. The accuracy requirements for these sheets are as follows: 7.4.2. 1 The projection grid and the control points shall be plotted correctly to the nearest one hundredth of an inch. The horizontal position of 90 percent of definitely recognizable points shall be correct with reference to the nearest control point within one fiftieth of an inch. 7.4.2.2 The contours shall faithfully express the relief detail and topographic shapes. In addition, 90 percent of the elevations or profiles in- terpolated from the contours shall be correct to within one-half of the specified contour interval and spot elevations shall be correct to the closest one tenth of a foot. 7.4.3 Final drafted topo sheets. The final drafted topo maps shall be on polyester drawing film (mylar) which is 30" x 42" (standard "F" size draw- ing) and shall have the appropriate grid lines drafted and designated (coordinate value) on each sheet. A north arrow and the declination between true north, magnetic north, and the assumed grid north shall be shown on each sheet. All drawing symbols used shall conform to standard symbols for AA-24