Contents & Foreword, Characterizing And ... - IRRI books

Fig. 6. Supervised classification of ERS time series, Luzon Province,Philippines. Classes are rice (yellow), urban area (red), layover (white),radar shadow (dark gray), rivers/open water (blue), and other (green).ing the wet season. In a second phase of the project, ERS radar data of the dry seasonare included to detect the dry-season rice areas (irrigated rice).Figure 7 (part of) shows the classification results of the SEARRI project combinedwith administrative boundaries. Validation is mainly done with the help of theIRRI provincial database on rice of the region (Hukes’ database). Although the Hukes’database estimates are only valid for the base year not later than 1995, it is the onlydatabase available at the required scale (covering Southeast Asia). In general, thetotal rice area from the radar classification is in accordance with the Hukes’ database(± 70% accuracy).Improvement of the rice map is needed for the occurrence and number of ricecycles throughout the season. Because of the heterogeneous spatial character of manyrice-growing areas, it is still difficult to detect all rice cycles using a limited numberof radar images.Using the area and number of cycles throughout the season from the classificationresults, rice production and methane emission maps are generated. Figure 8 showsthe yearly rice production per province.Monitoring rainfed and irrigated rice in Southeast Asia . . . 165