The total area for this project includes the entire state of South Carolina, encompassing 31,113 square miles. The geographic extent for the project is 32,189 square miles and 35,896 tiles of 5,000’ x 5,000’ orthoimagery, as illustrated on the map in Attachment E. Deliverable data must be continuous over the entire project area and must completely fill all tile boundaries and Counties/all data must be delivered in the calendar year. The Contractor shall provide orthoimagery in accordance with the below specifications. The Contractor shall map the entire state of South Carolina within the first year of the contract (unless granted an extension in accordance with section 3.13). SC Revenue and Fiscal Affairs (RFA) will require mapping of specific portions of areas during the subsequent years of the contract. RFA requires four-bands (blue, green, red, and near-infrared) be captured during flight, with at least 8-bits per band, 32-bit stacked. The final ground resolution of the orthoimagery will be 0.5 Ft per pixel for the entire project. A digital orthoimage is a digital image which has the properties of an orthographic projection. It is developed from a vertically oriented perspective aerial image by differential rectification so that the image displacements caused by camera tilt and terrain relief are removed. Imagery rectified from oblique imagery will not be acceptable for this project. The raw digital image file must be digitally rectified to an orthographic projection by processing each image pixel through the appropriate photogrammetric equations. This process requires as input, control information from airborne GPS-Inertial Measurement Unit (IMU) integrated system, supplemental control points, camera orientation parameters; and a Digital Terrain Model (DTM) or a Digital Elevation Model (DEM). To avoid confusion, the following definitions will apply: • Airborne GPS-IMU Integrated System – Camera position (latitude, longitude, and elevation) shall be recorded at the instant of exposure with airborne GPS. Airborne GPS data shall be differentially corrected and organized as individual data sets grouped by corresponding flight line. The IMU will allow the GPS unit to operate in the event GPSsignals are unavailable. The Contractor shall produce a statistical report summarizing the results of the airborne GPS adjustment. • Digital Terrain Model (DTM) – a rigorous data model which incorporates mass elevation points, spot elevations and breaklines at significant terrain breaks at a density level sufficient to support planimetric mapping and contour generation. In this case, planimetric mapping accuracy must be 4 feet RMSE or better (based on ASPRS Standard for Large Scale Mapping). The testing of the geospatial positional accuracy will conform to the NSDI Geospatial Positioning Accuracy Standards, Section 3.2 Table Part 3: Standards for Spatial Data Accuracy (FGDC–STD–007.3–1998). • Digital Elevation Model (DEM) – a less rigorous data model to be used for the purpose of creating a digital orthoimage which will support planimetric mapping accuracy of 1.5 feet RMSE or better (based on ASPRS Standard for Large Scale Mapping) when compared to image identifiable ground control points.
