Geometric accuracy analysis of the Geostationary Ocean Color Imager (GOCI) Level 1B (L1B) product

The Geostationary Ocean Color Imager (GOCI) has been used for many remote sensing applications to observe and monitor the ocean color of East Asia around the Korean Peninsula. However, to date, its geometric accuracy has not been thoroughly investigated; the only studies conducted so far have focused on verifying its radiometric quality. This study investigates the geometric accuracy of the Level 1B (L1B) product created from the GOCI geometric correction. The paper contains a brief description of the geometric correction process and an analysis of the positioning accuracy of GOCI L1B. Independent check points to assess accuracy were extracted from L1B and compared to their corresponding features in Google Maps, whose positioning accuracy has been thoroughly verified. Our analysis showed that, on average, the positioning accuracy of the GOCI L1B is ∼500-600 m, although there are differences in accuracy throughout the coverage area. It was confirmed that the GOCI L1B's overall accuracy fully meets geometrical image quality requirements (about 1 km). No specific bias pattern was identified, and there was little difference in accuracy throughout the acquisition time. The accuracy of the GOCI when landmark determination failed, e.g. due to a cloud, was further analyzed, and analysis showed that geometric quality was maintained even in the case of failure, although a slightly higher number of errors was observed. The experimental results support the hypothesis that the GOCI's geometric correction works well and provides sufficiently accurate positional information on ocean properties to be used for remote sensing applications.