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Comprehensive teaching plan to georeference Aerocam aircraft data, discuss uses, and address challenges, with exercises and practical steps.
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Teaching Plan for Preliminary Georeference for AEROCAM Aircraft Remotely Sensed Data • Review slides through georeferencing steps. • Open geo_aero project. • Georeference image 71 with the class. • Class exercise: georeference images 75 and 115 and add to image 71. • Open geo_exercise project. Add Aerocam mosaic. • Check surface temperature of the glacier and Chief Mtn. LCLU change. • Physical science issues and acknowledgement.
Objectives • Use ArcGis to georeference Aerocam aircraft data. • Discuss possible uses of Aerocam data to address • TRESTE objectives.
Challenges to Georeference AEROCAM and Other Aircraft Remotely Sensed Data • Geometry • Mirror • Flipped • Skewed • Aircraft Movement • Sun Angle 4. Data Overlap
Image Pixel Latitude and Longitude • Pixel resolution is 1 meter • 100 kilometers is 1 degree • 1 degree latitude is about 100 kilometers in length • 1 meter divided by 100,000 equals degrees per pixel or .00001
Estimating Control Points from the Center Control Point • Latitude: (48 + Latitude – 4800)/60 is the formula to convert from DMS to decimal degrees. • Longitude: (99 + (Longitude - 9900)/60)*-1is the formula to convert from DMS to decimal degrees. • http://www.geology.enr.state.nc.us/gis/latlon.html (DMS to DD converter) • Image sizes in pixels are 1912 horizontal and 1076 vertical. • From the center point, add .00538 for latitude to compute the top center point and subtract .00538 to compute the bottom center point – longitude is unchanged. • From the center point, add .00956 for longitude to compute the east image edge center point and subtract .00956 to compute the west image edge center point – latitude is unchanged.
Georeferencing Steps • Load image into ArcGis • Make sure layer is the image you want to georeference • Use dataframe properties to set geographic or coordinate projection system (GCS NAD83) • Add first control point in center of the image provided from aircraft instrument data (image size 1912 x 1076 pixels)
Georeferencing Steps Continued • Add control points at the top center and bottom center of the image (optional to add east and west center edge points) • Update georeferencing • Use rotate and move tools to position image to base map and/or other images • Pick additional control points to refine the georeferencing • Update georeferencing • Note – make sure units are in decimal degrees
Physical Science Questions • What is the magnitude of deforestation in the Chief Mtn. Area since 1992. (Use NLCD or in combination with MODIS LCLU) • What is the impact on land surface temperatures for LCLU changes? (Use MODIS LST in conjunction with LCLU datasets) • What is the surface temperature of the glacier? • What physical land surface features of interest can be observed with Aerocam? • Which of these features would be good candidates for monitoring with a second Aerocam flight?