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<br />photographs. (In platted areas, fences, power lines, and trees may be <br />omitted to achieve clarity.) Physical features that are referenced by a <br />respective name shall be so labeled on the finished map (e.g., street names, <br />etc.) and put on separate layers in the Auto CAD drawing. <br /> <br />G. Accuracy Standards. The contractor shall perform all mapping to comply <br />with these standards: 90% of all contours shall be within 1/2 of the <br />contour interval, and the remaining 10% shall not be in error by more than <br />I contour interval. 90% of the planimetric features shall be plotted to <br />within 1140" as measured at the map scale, and the remaining 10% shall be <br />plotted to within 1120". In areas where the ground is completely obscured <br />by dense brush or tree cover, contours shall be plotted as accurately as <br />possible from the stereoscopic model, while making full use of spot <br />elevations obtained where the ground is visible. Spot elevations shall have <br />the same tolerance as the cross section points. The mapping shall carry the <br />statement: "The map complies with National Map Accuracy Standards." <br /> <br />H. Spot Elevations. When the map distance between contour lines exceeds I" <br />in spacing, additional spot elevations from the plotter shall be shown. <br />Spot elevations shall be provided at all intersections of the center lines of <br />streets, roads, and streams. Spot elevations shall also be provided within <br />50' of any building or any small group of buildings that is not within the <br />limits of a city or a town or a platted subdivision. <br /> <br />1. Mylar Maps. All maps shall be photographically reproduced mylar <br />positives from the scribed negatives or compiled, edited manuscripts from <br />the plotter. The final map shall be four mil mylar, showing basic contours <br />and index contours by lines 0.008" wide and lines 0.012 wide for line base <br />mapping and lines 0.010" wide and lines 0.015" wide for photography <br />base mapping. Note: The lines shall be readable when reduced to a scale <br />1"=400'. <br /> <br />J. Monumentation. The CWCB may require the contractor to permanently <br />set monumentation for vertical and horizontal control. When required, the <br />monuments shall be brass caps firmly affixed to permanent structures or <br />rock outcrops; or they may be set in the top of concrete extending into the <br />ground to the frost-line depth, but not less than 36", as shown in Exhibit 2. <br />All monuments shall be set and referenced as described in Exhibits 2 and <br />3. <br /> <br />K. Control Markers. All permanent and semi-permanent control markers <br />used for mapping instrument surveys shall be shown and their respective <br />elevations labeled on the map. A summary listing showing northing, <br />easting, elevation, and a brief description of all control markers and <br />monuments is required. (See Exhibit 3.) <br />