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Alexander County, NC 2005 Digital Orthos


Download Link: http://data.nconemap.gov/geoportal/catalog/raster/download.page
Abstract: An orthoimage is remotely sensed image data in which displacement of features in the image caused by terrain relief and sensor orientation have been mathematically removed. Orthoimagery combines the image characteristics of a photograph with the geometric qualities of a map. For this dataset, the orthoimages were produced at a 0.5 foot pixel resolution for Alexander County, North Carolina, and was flown between 26 Feb 05 and 6 Mar 05.
Purpose: This data was developed to provide a spatially accurate, high resolution imagery to be used in the creation of other data layers. This Aerial Photography layer is also a primary base layer. (No attributes available).
Supplemental Information: Aerial photography was acquired utilizing a Wild RC30 aerial camera system with a six-inch focal length. This camera is equipped with a high resolution, distortion free lens and forward motion compensation. The photography was flown at 8,500 feet above mean terrain (AMT). The photography was flown with a 60 percent forward overlap and a 30 percent sidelap. During the time of image acquisition, two dual frequency GPS receivers were utilized. One receiver was operated on board the aircraft with the dual frequency antenna located directly over the camera. The shutter output from the aerial camera was directly connected to the receiver. The second receiver was used as a base station. These receivers were in constant operation during the photography mission and GPS phase data was collected at an epoch rate of 1 second. The airborne GPS data and IMU were used in combination with ground surveyed points to control the photography. The photography was scanned at a resolution of 7 microns and the imagery was orthorectified using the existing North Carolina Floodplain Mapping LiDAR Digital Surface Models (DSMs) that were subsequently edited down to bare earth returns only and Digital Elevation Models (DEMs) were generated.
Publication Date: 20060626
Originator: Alexander County Government
Publisher: EarthData International, Inc
Time Period of Content:
Time Period Information:
Range of Dates/Times:
Beginning Date: 20050226
Ending Date: 20050306
Currentness Reference: ground condition
Status:
Progress: Complete
Maintenance and Update Frequency: Unknown
Spatial Domain:
Bounding Coordinates:
West Bounding Coordinate: -81.368124
East Bounding Coordinate: -80.988983
North Bounding Coordinate: 36.055407
South Bounding Coordinate: 35.760393
Contact Organization: Alexander County IT Department - GIS Division
Contact Electronic Mail Address: gbrown@co.alexander.nc.us
Contact Voice Telephone: 828-635-3024
Contact Organization: Alexander County IT Department - GIS Division
Horizontal Datum Name: North American Datum of 1983
Planar Distance Units: survey feet
Ellipsoid Name: Geodetic Reference System 80
Map Projection Name: Lambert Conformal Conic
Distribution Liability: Although care has been taken in preparing the information contained in this data, Alexander County does not guarantee the accuracy thereof. Anyone using the data does so at their own risk and shall be deemed to indemnify Alexander County from any and all injury and/or damage arising from such use. This data may not be resold.
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