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Crop development information is critical to U.S. agricultural economy and decision making. In this paper, a general framework of Hidden Markov Models (HMMs) based corn progress percents esitmation method has been presented. Multivariate time series involving mean NDVI, fractal dimension, and Accumulated Growing Degree Days (AGDDs) are embedded into the modified HMM. Features of mean NDVI and fractal...
This paper proposes a new automated USDA National Agricultural Statistics Service (NASS) Cropland Data Layer (CDL) based method for stratifying U.S. land cover. The proposed method is used to stratify the NASS state level Area Sampling Frames (ASFs) by automatically calculating percent cultivation at the Primary Sampling Unit (PSU) level based on the CDL data. The CDL based stratification experiment...
The landscape spatial pattern with large scale has been the research focus of the landscape ecology recently, but few researches pay attention to that how to choose a perspective to study the characteristics of the landscape pattern of the Qinghai-Tibet Plateau for its unique topography and the alpine ecosystem. This paper takes the 2010 Western Mapping Data as the main data source and uses GIS as...
With the continuously increment of the available amount of spatial data sets, science, industry and administration require web-based geo-information concerning storage, availability and processing. The development of spatial data infrastructures (SDIs) bring about the Web-based sharing of large volumes of distributed geospatial data and computational resources. A powerful, dependable and flexible...
Rice is the world's most important crop for ensuring food security. Remote sensing has advantages in collecting data objectively and accurately on rice planting area, growth and development, and yield at large scales, but processing is slow due to vast amount of data, and there is need for an information extraction system specially designed for rice. This paper mainly discussed the key techniques...
Nowadays, Dongting Lake Wetland is facing with a series of ecological problems such as ecological deterioration, biodiversity reduction, ecological adjustment function decreasing. This study took the East Dongting Lake wetland as research area, and comprehensively evaluated the health status of wetland ecosystem by using of CBERS remotely sensed images. Firstly, the model of decision tree for classification...
Estimating crop leaf area index (LAI) based on remotely sensed observations is a normal way for regional crop monitoring and yield estimation in precision agriculture. However, the spatial heterogeneity in crop canopies and the nonlinearity of model for LAI estimation make differences between estimated-upscaled LAI (baseline data) and upscaled-estimated LAI. Then, aiming to reduce these differences,...
Because of the ability of describing the spatial distribution of land surface temperatures and land use, remote sensing images have been used to analyze the relationship between urban heat island (UHI) due to the land development effect and land use changes in recent years. To analyze subtropical urban microclimates and realize the man-made heat change due to the effect of land development, we compared...
The length of the crop season is a major determinant of yields in Sahel. Based on green-up onset detection derived from MODIS time series, this paper proposes a new methodology for the estimation of the sowing dates. It builds upon a novel stochastic model that translates vegetation onset detections around villages into sowing probabilities. Results for Niger show that this approach outperforms the...
It is essential for grain production, trade and grain security warning that the information on crop sown area is collected timely and accurately at regional and national level. The experiment on optimal design of spatial sampling schemes for estimating winter wheat sown acreage was conducted combining Remote Sensing, Geographic Information Systems with the traditional sampling methods as well as Geostatistics...
Land surface heterogeneity is effective on required sensor population of the regional or national telemetry networks used for agricultural information services. Temporary or permanently missing data sometime may occur in such large scale sensor networks due to type of failure. The agro-informatics measurement network (www.tarit.org) in Turkey is planned to have more than 30.000 sensors at 1200 stations...
Some remote sensing drought indices are being widely used in northern China, but seldom in humid regions of Southern China. Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature (LST) retrieved from Moderate Resolution Imaging Spectroradiometer (MODIS) sensor were used in Dongting Lake Basin and precipitation data from Tropical Rainfall Measuring Mission (TRMM) satellite as well...
Soil fertility is an extremely important indicator in measuring crop growth and largely affects the crop production potentiality. By comparing the traditional fertility assessment model and the GIS assisted fertility assessment model, we conclude that the GIS assisted method based on geostatistics and GIS technology is very effective in the assessment of soil fertility and widely used to evaluate...
The distributing map of surface reflectivity of Shanghai city and its adjacent areas is generated by MODIS remote sensing image. According to the surface spectrum features of this area and the changing characters of surface reflectivity caused by MODIS pixels, we explain the distributing map of surface reflectivity as follows. In the fifth wave band of MODIS, the distributing map of surface reflectivity...
Agricultural land quality monitoring is a fundamental and key work for national food security and cultivated land protection that ensures the sustainable development of agriculture. Traditional land surveys usually take long term and huge effort to conduct, while RS technologies are mainly used to monitor the quantity change of land resources. The changing information of the Natural Quality Index...
A quantitative dynamic knowledge model for evaluating the stability and analyzing the fluctuations of crop production was established in this study based on the results of farmland ecosystem stability and fluctuation of crop output. This dynamic model was combined with the technology of B/S distributive network structure and information management platform based on WebGIS to establish a Farmland Ecosystems...
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