PROJECT TITLE :

Rice Mapping Using RADARSAT-2 Dual- and Quad-Pol Data in a Complex Land-Use Watershed Cau River Basin

ABSTRACT:

Paddy rice crop mapping in Southern Vietnam can be done with synthetic aperture radar (SAR) thanks to the strong temporal backscatter signature of rice growing above the water's surface (Mekong Delta). Due to the complex land-use and land-cover in Northern Vietnam (the Red River Delta), rice mapping using SAR is difficult to accomplish and is only occasionally carried out in this region. However, in order to perform hydrological simulations in river basins such as the Cau River basin, it is necessary to have information about rice fields. The primary objective of this study is to investigate the potential of RADARSAT-2 band-C in identifying rice fields across a large and fragmented land-use area. Two methodologies are suggested, one for each data type, and both of them are tailored to the land-use and land-cover characteristics of the research area. To the HH like-polarized ratio of dual-pol data, the thresholding technique was applied, along with a statistical analysis of the temporal variation of rice backscattering. The full quad-pol and a single HH-polarization that was calculated from polarimetric data were both subjected to the support vector machine (SVM) algorithm. This study demonstrates that data from RADARSAT-2's dual- and quad-pol sensors can be used effectively to locate and identify rice fields that have been cultivated. On the other hand, it appears that the quad-pol data are more effective than the dual-pol data, and the SVM classification appears to be more adaptable than the thresholding technique. The overall classification accuracy shows that the results derived from the single HH polarization are 3 to 10% less accurate than those derived from the classification of full quad-pol data. This is based on comparing the accuracy of the results derived from the single HH polarization to those derived from the classification of full quad-pol data. The findings demonstrate that polarimetric C-band data can be useful for the identification of rice fields in Northern Vietnam.