共查询到20条相似文献,搜索用时 15 毫秒
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Zhangyu Dong Zongming Wang Dianwei Liu Kaishan Song Lin Li Mingming Jia Zhi Ding 《Journal of the Indian Society of Remote Sensing》2014,42(3):569-576
Increasing interest in wetlands for environmental management requires an understanding of the location, spatial extent, and configuration of the resource. The National Wetlands Inventory is the most commonly used data source for this information. However, its accuracy is limited in some contexts, such as agricultural and forested wetlands. An large number of studies have mapped wetlands worldwide from the perspective of land use and land cover change. However, information on the actual wetland planting areas annually is limited, which greatly impacts ongoing research. In this case study of the West Songnen Plain, we developed a simple algorithm for the quick mapping of wetlands by utilizing their unique physical features, such as annual display of phenological land-cover change of exposed soils, shallow flooding water, and plants from multi-temporal Landsat images. Temporal variations of the Normalized Difference Vegetation Index (NDVI) and Land Surface Water Index (LSWI) derived from Landsat images in 2010 for wetlands at different growth stages were analyzed. Results show that during the ante-tillering phase, the NDVI value (above zero) is lower than the LSWI value of paddies because of flooding of shallow water; during the reproductive and ripening phases, the NDVI value is higher than the LSWI value (above zero); and during the post-harvest wetland planting phase, the NDVI value is still higher than the LSWI value, but the LSWI value is negative. Wetland areas can be detected using one or two images in the optimum time window. The algorithm based on the difference of NDVI and LSWI values derived from Landsat images was used to extract the actual wetland planting area. Validated alongside statistical data, the algorithm showed high accuracy. Therefore, this algorithm highlights the unique features of wetlands and can help in mapping the actual wetland area annually on a regional scale. Results further indicate that the new method has a classification accuracy of 92 %. In comparison, two traditional methods based on Landsat-7/ETM registered accuracy rates of only 83 % and 87 % respectively. 相似文献
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以陕甘宁地区为研究区、2001—2015年的MODIS遥感影像为数据源,基于MODIS像元的植被丰度提出了累积曲线梯度变化法,通过提取沙漠化界线确定了用植被丰度表达的界线指标,讨论了陕甘宁地区的沙漠化变化。结果表明:(1)基于数学统计分析方法的累积曲线梯度变化法,方法简单、可操作性强,为沙漠化的定量分析与动态监测提供了新方法;(2)以植被丰度15%为指标作为陕甘宁地区的沙漠化界线,发现在这15年间,陕甘宁地区的沙漠化呈现在波动中不断改善的总体趋势。 相似文献
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Urban models are evolving to require more and more detailed data that in many cases have to be spatially disaggregated from larger zones. This paper deals with the disaggregation of statistical data in an urban context in which land use data are available at a less detailed level. With the availability of land use data, the traditional approach of areal weighting is improved with an areal and land use weighted approach. This weighted approach is further elaborated to include homogeneous weight zones (HWZ) so as to reflect general geographical variations among the same land use type. A case study in Wuhan, China has demonstrated the effectiveness of the doubly weighted approach within the specified context. 相似文献
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Using Spatially Explicit Simulated Data to Analyze Animal Interactions: A Case Study with Brown Hyenas in Northern Botswana 总被引:1,自引:0,他引:1
Jennifer A. Miller 《Transactions in GIS》2012,16(3):271-291
New developments in global positioning systems (GPS) and related satellite tracking technologies have facilitated the collection of highly accurate data on moving objects, far surpassing the ability to analyze them. Within geographic information science, ‘movement pattern analysis’ (MPA) has developed as a subfield that addresses concepts and theories used to explore the spatio‐temporal structure in data, although the methodological and analytical framework associated with MPA is new and still evolving. Interactions between individuals can be considered a second order property of movement and have been far less studied. The nature of interactions between individuals in a population is a fundamental aspect of a species' behavioral ecology and information on the frequency and duration of these interactions is vital to understanding mating and territorial behavior, resource use, and infectious disease epidemiology. The focus of this work was to explore how spatially explicit simulated data can be used to analyse dynamic interactions between individuals. Five different techniques that have been used to quantify dynamic interactions based on GPS data of pairs of individuals were utilised, and all were compared in the context of spatially explicit simulated data intended to represent biologically realistic null models for individual movement, and subsequently paired interactions. 相似文献
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The present study describes a procedure for quantitatively analyzing satellite telemetry data to identify interspecific land use differences among four threatened crane species. The inherent inaccuracy of satellite telemetry data points, the temporal autocorrelation of those points, and the resolution of two land‐cover imagery products from the IGBP‐DISCover Global Land‐Cover Characterization Project (derived from AVHRR data) were assessed and integrated in a GIS. Satellite telemetry is a system where animals are tracked using battery‐operated transmitters and locations are calculated using triangulation from satellites. Using the variable spatial inaccuracy of the telemetry locations, each point was buffered using a radius based on the accuracy of the point, and then intersected with the land cover imagery. The research concluded that the methodology is valuable for studies of birds at a regional scale, with interspecific differences clearly evident, but that diurnal and nocturnal differences were not discernable due to the coarse resolution of both satellite telemetry and land‐cover data. 相似文献
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A Case Study on Forewarning of Yellow Rust Affected Areas on Wheat Crop Using Satellite Data 总被引:2,自引:0,他引:2
Sujay Dutta Suresh Kumar Singh Mukesh Khullar 《Journal of the Indian Society of Remote Sensing》2014,42(2):335-342
Objective of this study was to identify stripe rust affected areas of wheat crop as well as evaluation of remote sensing (RS) derived indices. Moderately low temperature and high humidity favour the growth of yellow rust. Most affected areas of Punjab are the foothill districts such as Gurdaspur, Hoshiarpur and Ropar. Occurrence of yellow rust is possible when maximum temperature for day is below 15 °C and Temperature difference of day’s maximum and minimum temperature is less than 5 °C during the early growth of wheat. Forecast of the infestation was done using 3 days forecast of weather data obtained from Weather Research and Forecasting (WRF) model at 5 km resolution. Weather forecast used was obtained from Meteorological and Oceanographic Satellite Data Archival System (MOSDAC) site and post infestation, identification of specific locations were done using multi-date IRS AWiFS data. It is an attempt for early detection through 3 days advance forewarning of weather which will be handy tool for planners to expedite relief measures in case of epidemic with a more focused zones of infestation as well as for crop insurers to know the location and extent of damage affected areas. 相似文献
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Infestations of corn rootworms (Coleoptera: Chrysomelidae) create economic and environmental concerns in the Corn Belt region of the United States. To supplement the population control tactics of areawide pest management programs, we believe that a better understanding of the spatial relationships between biotic and abiotic or physical factors at the landscape scale is needed. Our research used several geographical information systems (GIS) and spatial analytical techniques to examine relationships between corn rootworm metapopulation dynamics, soil texture, and elevation. Within GIS, several spatially explicit procedures were used that include an interpolation technique, spatial autocorrelation analysis, and contingency analysis. Corn rootworm metapopulation distributions were found to be aggregated and related to soil texture and elevation. We review techniques and discuss our preferences for using particular spatially explicit procedures. The information derived from the spatial analyses demonstrates how GIS can be used in areawide pest management to provide inputs for spatially explicit models to predict future pest populations and formulate more well‐informed pest management decisions. The techniques described in this paper could easily be extended to study the spatial dynamics between other pest populations in agricultural landscapes. 相似文献
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国土资源数据高效存储技术及策略是国土资源信息化的基础。本文基于对省内多级行政单元国土资源数据特征及管理需求分析,提出了省内多级行政单元国土资源数据应用模式及数据布局策略,并以陕西省实际数据为例,对省级土地利用数据库的地类图斑要素层,按县级多实例、全省单实例(不进行布局控制)和全省单实例(按县进行数据库分区布局)三种布局策略下的数据访问性能进行了测试和对比分析,形成了对我国国土资源数据管理部门具有重要参考价值的结论。 相似文献
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G. P. Obi Reddy M. S. S. Nagaraju I. K. Ramteke Dipak Sarkar 《Journal of the Indian Society of Remote Sensing》2013,41(2):331-343
In the present study, landforms and soils have been characterized in Borgaon Manju watershed of basaltic terrain located in Akola district, Maharashtra, Central India. Terrain characterization using Shuttle Radar Topography Mission (SRTM) elevation data (90 m) and IRS-P6 LISS IV data in conjunction with adequate field surveys shows nine distinct landforms. Soil resource inventory shows fourteen soil series in the study area. Soils formed on gently sloping (3–8 %) subdued plateau are very shallow (23 cm), moderately well drained, moderate (15–40 %) surface stoniness, severely eroded, clayey and slightly alkaline in reaction, whereas, the soils formed on level to nearly level (0–1 %) slope in the main valley are very deep (>150 cm), well drained, very slight (<3 %) surface stoniness, moderately eroded with clayey surface and moderately alkaline in reaction. Soils in the watershed are grouped into Lithic Ustorthents, Vertic Haplustepts, Calcic Haplustepts, Typic Haplustepts, Typic Haplusterts and Sodic Calciusterts. The study demonstrates that the analysis of SRTM elevation data and IRS P6–IV data in Geographic Information System (GIS) with adequate field surveys helps in characterization of landforms and soils in analysis of landscape-soil relationship. 相似文献
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This paper integrates genetic algorithm and neural network techniques to build new temporal predicting analysis tools for geographic information system (GIS). These new GIS tools can be readily applied in a practical and appropriate manner in spatial and temporal research to patch the gaps in GIS data mining and knowledge discovery functions. The specific achievement here is the integration of related artificial intelligent technologies into GIS software to establish a conceptual spatial and temporal analysis framework. And, by using this framework to develop an artificial intelligent spatial and temporal information analyst (ASIA) system which then is fully utilized in the existing GIS package. This study of air pollutants forecasting provides a geographical practical case to prove the rationalization and justness of the conceptual temporal analysis framework. 相似文献
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S. Movaghati F. Samadzadegan A. Azizi 《Journal of the Indian Society of Remote Sensing》2013,41(1):21-33
Detecting fires, which are at their early stages is the first component of effective fire fighting. To date, several algorithms have been proposed to detect fire spots using remote sensing data. Nevertheless, in order to be able to accurately detect small and cool fires, which are very important at the regional scale, most of these algorithms need to be adjusted and improved. In this paper, an agent-based algorithm is presented for regional forest fire detection using bi-temporal MODIS data. The algorithm is designed to be so self-adaptive and consistent that it could be applied to the different pairs of consecutive images taken by the same satellite platform and at the same daytime. The results clearly show that compared with the MODIS contextual algorithm (version 4), the proposed method is more sensitive to small and cool forest fires in Iran. 相似文献
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针对参心坐标系向地心坐标系转换后数据处理方法存在的缺陷,本文以数字线划图(DLG)分幅数据为例,结合CMAP软件,提出了批量处理方法,完成数据的批量拼接、快速坐标转换以及转换后数据的编辑、裁切等工作,批量生产了满足图式规范要求的标准分幅DLG数据,同时能较好地解决批量DLG数据坐标转换后存在的问题。该方法有效地减少了生产中的重复性,提高了生产效率,并为以后分幅数据坐标转换批量生产奠定了良好的基础。 相似文献
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国土资源数据高效存储技术及策略是国土资源信息化的基础,本文基于对省内多级行政单元国土资源数据特征及管理需求分析,提出了省内多级行政单元国土资源数据应用模式及数据布局策略,并以陕西省实际数据为例,形成了对我国国土资源数据管理部门具有重要参考价值的结论。 相似文献