Screening Method of Paddy Fields Targeted for Field Surveys during Investigations on the Status of Generation and Elimination of Devastated Farmlands Using Multitemporal Satellite Data and Paddy Parcel Boundary Data

Abstract

In order to contribute to labor saving in the field surveys during investigations on the status of generation and elimination of devastated farmlands, we propose a method to extract paddy fields that may be devastated, that is, a screening method of paddy fields targeted for field surveys based on the parcel mean values of NDVI using multitemporal satellite data and paddy parcel boundary data. We conducted extractions in Inashiki-city and Chikusei-city, Ibaraki Prefecture using RapidEye satellite data (some ALOS satellite data used) acquired in May, July, and August, and paddy parcel boundary data by the proposed method. Then, we examined the screening efficiency, which is the percentage of the actual devastated paddy fields in the extracted paddy fields that were thought be devastated, using field survey data. As a result, the screening efficiencies were 89% for the Inashiki A area, 74% for the Inashiki B area, and 47% for the Chikusei area. The screening efficiency was low in the Chikusei area because there were many paddy fields where crops were not planted after harvest of wheat (winter crops), and weeds overgrew some of the paddy fields in summer.