Orthorectification of GeoEye-1 satellite imagery of northern Macquarie Island, captured 10 October 2011

The Australian Antarctic Data Centre (AADC) has GeoEye-1 satellite imagery of northern Macquarie Island, captured 10 October 2011. The satellite provides panchromatic imagery with 0.41 metre resolution and multispectral imagery with 1.65 metre resolution.

The panchromatic and multispectral bands were orthorectified using the RPC data files and the AADC's 5 metre resolution Digital Elevation Model of the island (see metadata record 'Macquarie Island AIRSAR DEM (Digital Elevation Model)', Entry ID: macca_dem_gis). The RPC orthorectification process works on a pixel-by-pixel basis to provide correct ground locations. The orthorectified image files are called GE_10Oct2011_pan_orc and GE_10Oct2011_ms_orc. These two images were then pansharpened using Gram-Schmidt spectral sharpening, the resulting image is called GE_10Oct2011_ps_orc.

The processing was done by Angela Bender of the AADC using IDL/ENVI version 4.8. The DEM was unprojected before the orthorectifications were done as ENVI version 4.8 requires a DEM, if used, to be unprojected.

Ground control points compiled by Angela Bender for the area covered by the image are provided (see a Related URL) but were not used in the orthorectification process. The ground control points were sourced from the AADC's survey control database and topographic data. The ground control points could be used for future orthorectifications.

The pansharpened image could be coregistered with an orthorectified Quickbird image captured 15 March 2005 (see metadata record 'Macquarie Island Quickbird Image (15 March 2005) orthorectification', Entry ID: Macquarie_Quickbird_15Mar2005) using 'image to image' transformation.

If this was done, the ground control points mentioned above could be used as a check of the coregistration. They could also be used to get an error estimate of the orthorectified Quickbird image.