Orthorectification of an Ikonos panchromatic image

Satellite images are used since a lot of time in remote sensing. Several and various information and applications derive from remote sensing data: agriculture monitoring and analysis, land's humidity, pits and dumps location, coast pollution estimation, small and medium cartography scale, and many other else. Until now, for these kind of application, have been used satellite images with peculiar radiometrical and spectral resolution, anyway characterized by low geometrical resolution (10-100 m). Recently, satellite images with high geometrical resolution (about 1 m as Ikonos, Space Imaging Inc.) became available, and this open a new era for digital mapping. The most important characteristics of these satellites are: the high resolution and geometric accuracy, the possibility (user defined) to program the acquisition of new images, stereo capability, and the ability to revisit any location almost every day. As a consequence, it is interesting to analyses the use of the Ikonos images as orthophotos or as support for mapping production and updating. In this preliminary work we studied the accuracy obtained in the orthorectification of Ikonos panchromatic image recorded on urban area (near Ferrara, Italy). To orthorectified the high resolution satellite image (by the OrthoEngine 7.0 PCI) and to check our results (planimetric accuracy), we used many GCPs measured by rapid-static GPS surveying. Our results show the importance to use precise GCPs versus GCPs obtained from pre-existing numerical cartography.