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<br />,'. <br /> <br />. <br /> <br />. <br /> <br />DEM Data <br /> <br />1. All data will be delivered in Colorado State Plane Central Zone coordinate <br />system with NAD83 (1992) (horizontal) and NAVD88 (vertical) datum and <br />units will be in US Survey Feet unless otherwise specified prior to contract <br />authorization. <br /> <br />2. Absolute DEM accuracy will be 15 cm (6 inches) Root Mean Square Error <br />(RMSE) (or 1-sigma) vertical and 1-meter RMSE (1-sigma) horizontal. <br /> <br />3. DEM data will be based on a digital elevation model consistent with the <br />United States Geologic Survey (USGS) National Mapping Program DEM <br />Accuracy Standard. DEM data shall be acquired and processed in <br />accordance with the latest Federal Emergency Management Agency (FEMA) <br />Light Detection and Ranging (L1DAR) mapping guidelines. <br /> <br />4. Nominal elevation sample spacing will be approximately 3 to 5 meters (9 to <br />15 feet). <br /> <br />5. Vegetation effects will be processed using an automatic removal process of <br />the contractors choosing, yielding approximately 90 to 95 percent removal of <br />vegetation from data. It is recognized that the effectiveness of automated <br />vegetation removal may decrease under leaf-on conditions. <br /> <br />6. Manual removal of structures and buildings will be performed on the data <br />consistent with FEMA and ACOE standards and requirements. <br /> <br />7. Contours at 2-foot vertical interval will be generated by interpolation of the <br />DEM data. <br /> <br />Digital Images <br /> <br />1. Absolute horizontal accuracy of image data will be 2 meters RMSE (1-sigma). <br /> <br />2. Image spatial pixel resolution will be approximately 0.3 meters Ground Sample <br />Distance (GSD). <br /> <br />3. Digital panchromatic image data will be orthorectified using corresponding <br />airborne GPS, platform altitude and DEM data. <br /> <br />4. Each image will be 2024 x 2024 pixels in size, High-resolution othorectified <br />images will be mosaiced into areas the same size as DEM models. <br /> <br />Page 2 of3 <br />