Kim, Hyun-Ok; Yeom, Jong-Min (2015). Sensitivity of vegetation indices to spatial degradation of RapidEye imagery for paddy rice detection: a case study of South Korea. GISCIENCE & REMOTE SENSING, 52(1), 1-17.

Abstract
Satellite remote sensing is an essential tool for crop monitoring over large areas. One of the most practical issues is defining the appropriate spatial resolution level in terms of technical aspects such as orbit path, swath width, or revisit rate, particularly in South Korea where the major agricultural activity of rice cultivation is conducted mostly by private farmers on small parcels of land. This study is an experimental approach to examine the sensitivity of vegetation indices of three paddy rice crops at various spatial resolutions during two seasons (July, September) using RapidEye multi-spectral image data. The results showed that lower spatial resolutions (beyond 26m) had higher uncertainty for reflecting homogeneous field conditions and differentiating crop species. We stress, however, that the appropriate resolution might be dependent on the actual paddy size in the fields. Regarding the phenology of rice plants, the spectral difference of vegetation indices was more dependent on the same spatial resolution in July than in September. In addition, the July imagery, in which the vegetative and reproductive growth stages of the various rice cultivars were mixed, was slightly more effective for differentiating paddy rice crop classes. As an additional benefit, provision by RapidEye of red-edge spectral information ensured that a transformed vegetation index that made use of the red-edge band, which was edgNDVI in this study, was more applicable for differentiating three paddy rice crops in homogeneous rice cultivation.

DOI:
10.1080/15481603.2014.1001666

ISSN:
1548-1603