Publication Date:
2022-01-12
Description:
Abstract
Description:
Measurement errors in orthorectified images are very important when it comes to checking the subsidies claims made by European farmers. The Control with a Remote Sensing (CwRS) Programme, managed by the GeoCAP and CID actions of the Monitoring Agricultural Resources Unit of the EC Joint Research Centre (JRC), requires the establishment of guidelines to be applied by Member States when using remotely sensed images to verify farmers’ claims under the EU Common Agriculture Policy (CAP) subsidies. The area of land parcels used for farming are verified based on very fine spatial resolution (VHR) orthoimages that must meet specific geometric and visual qualities. As such, all VHR orthoimages used within this context must meet or exceed the EU standard as reported in Kapnias et al. (2008), based on external quality control (EQC). EQC is based on the root mean square error (RMSE) between the true geographic position and the image position of the independent check points (ICPs). The ICPs are points not included in the sensor model parameter estimation process and are derived from an independent source, preferably of higher accuracy. This report presents the applied EQC methodology and the geometric quality results recorded for the four samples of the KOMPSAT-2 (K2) radiometrically corrected images (processing level 1R), acquired over the JRC Maussane Test Site. The key issues identified during the testing based on the limited KOMPSAT-2 sample images that were made available to us are as follows: (a) The 1D RMS errors measured on the final K2 orthoimage after the single scene correction applying either the PCI rigorous model, the PCI RPC-based or the ERDAS RPC-based model are not sensitive to the number of GCPs used if they are well-distributed and range between 9 and 15 (provided a DTM with 0.6 m vertical accuracy), and they are sensitive to the overall off-nadir angle and increase with increasing off-nadir angle, (b) The average 1D RMSE are 2.1 m and 4 m, while the maximum 1D RMSE values are 3.2 m and 6.2 m of easting and northing direction respectively, provided that a DTM with 0.6 m vertical accuracy and GCPs with mean RMSE-X (in X direction) and RMSE-Y (in Y direction) values of 0.6 m are used, and (c) The orthorectified KOMPSAT-2 images do not fall within the accuracy criteria of the CwRS 1:10000 scale requirements, i.e. an absolute 1D RMSE not exceeding 2.5 m, except where the images are characterized by an overall off-nadir angle close to zero degrees, and the rigorous model or first order Rational Polynomial sensor model is applied.
Description:
SeriesInformation
Description:
Proceedings on the Workshop of Remote Sensing Methods for Change Detection and Process Modelling, 18-19 November 2010, University of Cologne, Germany, Kölner Geographische Arbeiten, 92, pp. 109-115
Keywords:
Other
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None
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Remote Sensing Methods
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Remote Sensing
Type:
Text
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Book Section
Format:
1127 Kilobytes
Format:
7 Pages
Format:
PDF
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