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本文运用面向对象分类与DEM数据相结合的方法,对资源卫星一号02C卫星遥感影像进行湿地提取。探索了基于对象与DEM信息的提取技术,在02C影像湿地的提取应用,对研究我国国产卫星在湿地监测和保护方面有重要的意义。研究结果表明：（1）面向对象的遥感影像信息提取方法,可同时兼顾影像光谱信息及空间信息,适用于02C影像的湿地提取,精度得到明显提高;（2）基于对象与DEM信息的提取方法,使沼泽地与草地相混淆的现象明显减轻,湿地分类精度进一步提高,该方法适用于高分辨率遥感影像的湿地提取研究;（3）基于对象与DEM信息提取的水田、水体、沼泽地及河滩的精度,分别为88.46%、97.44%、86.96%和83.33%,满足资源卫星一号02C遥感影像对湿地进行监测和保护的需要。 相似文献
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为探究不同测量方法获取浅沟数据的精度,本文以元谋干热河谷区浅沟为例,采用RTK、三维激光扫描、近景摄影测量等多种测量方法获取浅沟数据,建立DEM并提取浅沟形态参数,对比近景摄影测量以不同方式获取标记坐标后建立DEM的差异,同时以测针板实测浅沟横剖面为参照,对比分析不同测量方法获取浅沟横剖面的精度。结果表明：RTK获取密度较低的点数据,建立的DEM较粗糙,仅体现沟缘大致走向;近景摄影测量+RTK方法测得的DEM高程整体低于近景摄影测量+全站仪所得DEM高程;利用三维激光扫描仪和近景摄影测量+全站仪两种方法获取数据所提取的浅沟形态参数精度较高;对比浅沟横剖面,横剖面近景摄影测量+全站仪测量所得与实测横剖面重合度较高。因此,利用近景摄影测量+全站仪进行浅沟测量,在精度、效率等方面优势较大。 相似文献
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针对当前医疗资源分布不均的问题,本文以莱西市为例,以行政村为最小研究单元,借助GIS空间分析技术,采用改进的两步移动搜索和潜能模型法,对莱西市医疗设施空间可达性进行研究.结果表明:莱西市整体的医疗资源分配不均,具有明显的空间集聚特征,高值区域主要集中在中部地区,包括水集街道、沽河街道、望城街道和莱西经济开发区;低值区域... 相似文献
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Chunye Lin Yumeng Xue Xuan Zhang Duanzhi Renqin Xueli Zhou Yuanxin Cao Bobo Guo Xitao Liu 《Environmental Earth Sciences》2018,77(4):153
Lake Qinghai in the Qinghai-Tibet plateau is the largest lake in China. This study firstly reported the geochemistry of Cd in the lake. Water samples were collected from Lake Qinghai (n = 69) and Buha River (n = 12), while sediment (n = 22) and topsoil (n = 45) samples were collected from the lake and around the lake area, respectively. In addition, pore water samples (n = 20) were separated from sediment samples. Water samples were analyzed for pH, K, Na, Ca, Mg, Cl, S, and Cd, while sediment and topsoil samples were analyzed for K, Na, Ca, Mg, Al, Fe, Mn, S, Sc, and Cd. The average concentration of Cd was 0.014 μg L?1 in the water of Lake Qinghai and 0.007 μg L?1 in the water of Buha River. However, the average concentration of Cd was 0.320 μg L?1 in the sediment pore water, much higher than that in the lake water and river water. Cadmium concentration in the lake water might be mainly controlled by salinity, while it in the pore water might be mainly controlled by carbonate minerals. Cadmium concentration in the river water might be controlled by alkalinity and pH. The average concentration of Cd in the sediment was 0.284 mg kg?1. The enrichment of Cd in the lake sediment was significantly higher than that in the topsoil around the lake. Anthropogenic atmospheric deposition of Cd did not led to the increase in dissolved Cd level in the lake water, but led to its enrichment in the lake sediment. 相似文献
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The spatial and temporal distribution of forest fires displays a complex pattern which strongly influences the forest landscape and the neighbouring anthropogenic development. Statistical methods developed for spatio-temporal stochastic point processes can be employed to find a structure, detect over-densities and trends in forest fire risk and address towards prevention and forecasting measures. The present study considers the Portuguese mapped burnt areas official geodatabase resulting from interpreted satellite measurements, covering the period 1990–2013. The main goal is to detect whether space and time act independently or whether, conversely, neighbouring events are also closer in time, interacting to generate clusters. To this purpose, the following statistical methods were applied: (1) the geographically weighted summary statistics, to explore how the average burned area vary locally through the investigated region; (2) the bivariate K-function, to test the space–time interaction and the spatial attraction/independency between fires of different size; and (3) the space–time kernel density, allowing elaborating smoothed density surfaces and representing over-densities of large versus medium versus small fires and on north versus south region. The proposed approach successfully allowed finding and mapping spatio-temporal patterns within this large data series. Specifically, medium fires tend to aggregate around small fires, while large fires aggregate at a larger distance and longer times, indicating that the return time following these events is longer than for small and medium fires. The density maps shows that hot spots are present almost each year in the northern region, with a higher concentration in the northern areas, while the southern half of the country counts lower surface densities of fires, which are mainly concentrated in the central period (2000–2007). 相似文献
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基于地缘影响力模型的大国地缘政治博弈——以钓鱼岛问题背景下的中美博弈为例 总被引：3，自引：1，他引：2
大国地缘政治博弈事关国家安全,影响世界格局。通过对地理要素的综合考量构建了地缘影响力模型,并基于博弈论建立了钓鱼岛问题大国地缘政治博弈树,对中美博弈过程进行了分析。最后针对钓鱼岛问题4种博弈走势提出了战略应对参考建议。研究结果表明：①在中国大陆主导时,各国保持合作将共赢,一旦动武,若美俄地缘战略决策指数不高,形势对中国大陆不利。②当美国地缘战略决策指数较小,俄罗斯较大时,是解决钓鱼岛问题的战略良机。③中国台湾是中国解决钓鱼岛问题的重要影响因素,要灵活把握与处理。④ 在4种战略博弈形势下,均存在中美战略博弈的纳什均衡,但美国、日本和中国台湾有一定概率铤而走险,要保持警惕并做好战略应对。⑤ 博弈分析结果较为客观的反映了钓鱼岛问题的多种战略走向,并与当前相关大国关于钓鱼岛问题的战略基本吻合,印证了地缘影响力模型对地理要素量化的可行性以及大国地缘政治博弈分析方法的合理性。 相似文献
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为准确把握新鹤海湾的演变特征和水动力条件,采用现场观测和GIS技术对其地形变化、冲淤分布和冲淤量进行探讨,并利用数值模拟分析波浪、潮流和泥沙共同作用对海湾演变的影响。结果表明:海湾演变对连续台风的响应不同,表现为先冲后淤,其中苏拉作用下的冲刷量为台风过境后全年的2倍左右;受东南季风的影响,春夏冲淤幅度较大,海湾冲淤分布为南冲北淤,波高分布不均与涨潮流入湾时的向北偏转是其主要原因;波流共同作用下的底床切应力约为潮流单独作用时的10倍,波浪是导致海湾冲刷的主要因素,常浪下底床切应力小于临界冲刷应力,泥沙不易起动,因此海湾冲刷主要是由极端天气时的大浪所导致的。 相似文献
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针对广西茅尾海入海河口池塘养殖污染问题,本文利用无人机多光谱遥感影像和实测水质数据,建立了反映水体营养状态的叶绿素a (Chl-a)、化学需氧量(COD)、悬浮物(SS)、总氮(TN)、总磷(TP)5种水质参数,反演光谱特征及遥感反演模型,并利用湖泊综合营养指数法对水体富营养化状态进行评价。研究结果表明:①Chl-a与蓝、近红外波段相关性显著,COD与红、红边波段相关性显著,SS与红边波段相关性显著,TN与近红外波段相关性显著,TP与蓝、绿波段相关性显著;②在建立的几种水质参数反演模型中,二次多项式函数反演模型综合效果最佳;③池塘养殖区水体富营养指数多集中在60～80,属于中度和重度富营养化程度,且近岸水体富营养化程度大多低于远岸。 相似文献