Brazil Soybean Area Estimation Based on Average Samples Change Rate of Two Years and Official Statistics of a Year Befor
Comprehensive, reliable and timely information of Brazil’s soybean area is necessary for China to make decisions on agricultural related problems. Spatial sampling method which combined remote sensing and sampling survey is widely used. Due to limitations
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Abstract. Comprehensive, reliable and timely information of Brazil’s soybean area is necessary for China to make decisions on agricultural related problems. Spatial sampling method which combined remote sensing and sampling survey is widely used. Due to limitations of width and revisit cycle of medium resolution satellite, This study designed a typical investigation method about Brazil soybean area based on average samples change rate of two years and official statistics of a year before, typical samples were selected to survey, sampling frame was constructed on soybean planting state, the sampling unit was designed as 40 km × 40 km, the sampling proportion was 2 %, average samples change rate of two years were 2013 and 2014. Estimated area was compared with Brazil official harvested area in 2014 (published on 2015 April by Brazilian Institute of Geography and Statistics), the relative error is 2.37 %. Keywords: Brazil soybean area estimation Change rate of two years Official statistics of a year before Sampling
1 Introduction Chinese soybean planting area has decreased year by year, soybean self-supply ability had been to about 20 % in 2013, mainly imports country are United States, Brazil, and Argentina [1]. Comprehensive, reliable and timely information of Brazil’s soybean area is necessary for China to make decisions on agricultural related problems. Compared with the traditional survey method, Remote sensing survey has advantage of large coverage, low cost and less investigation time [2]. Spatial sampling method which combined remote sensing and sampling survey is widely used in the investigation of large scale crop area estimation [3]. The survey accuracy is mainly effect by Population, sampling proportion, sample distribution. Population can be defined by
© IFIP International Federation for Information Processing 2016 Published by Springer International Publishing AG 2016. All Rights Reserved D. Li and Z. Li (Eds.): CCTA 2015, Part I, IFIP AICT 478, pp. 366–374, 2016. DOI: 10.1007/978-3-319-48357-3_36
Brazil Soybean Area Estimation Based on Average Samples
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historical cultivated land [4] or administrative divisions with historical statistical data [5]. Sampling proportion is the bigger the better with the premise of meeting the minimum sampling proportion, but the actual survey should consider the accuracy requirements, cost and time. The ideal sample distribution is random distribution, but it is subject to the satellite width limitation and revisit cycle. With the rapid development of remote sensing technology, medium resolution satellite (10 m–30 m) are gradually meet the sampling survey requirements and even full coverage. But in the soybean growth period, it is difficult to get full coverage image with cloud free. Considering the weather, satellite width limitation and revisit cycle, using landsat7/8 as a data source, this study designed a typical investigation method about Brazil soybean area estimation based on average samples change rate of two years and official statistics of a year before.
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