Product 1 - Ortho-rectified scene

Product 1 scenes correspond to the path/row of the Landsat orbit. This image (204033) was acquired on 24th June 2000, and as with all Image2000 product 1 scenes, was ortho-corrected.

The ortho-correction method consisted of using a physical model of the satellite's flight during the scene acquisition, which is then complemented with Ground Control Points (GCP's) and a Digital Elevation Model (DEM). Map projection information is attached to the model. The resulting product has excellent accuracy between the spectral bands, sub-pixel location accuracy throughout the image and excellent preservation of radiometric characteristics.

The geometric correction was done on a Country basis - according to the relevant national map projection system(s). A rigorous orbital model was used. Control point measurements were used in a weighted least squares adjustment to estimate optimal values for the orbital and attitude parameters. The adjusted parameters were used to resample by cubic convolution the raw scene in a single step, instead of the usual two step procedure of first producing a system-corrected scene and then resampling a second time, thus causing unnecessary smoothing of the data. The final pixel size after resampling is 12.5m for the panchromatic band, 25m for the multispectral bands and 60m for the thermal band. All the ortho-rectified scenes are well within the requirement of Root Mean Square Error (RMS) <25m.


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