共查询到20条相似文献，搜索用时 625 毫秒
1.
2.
3.
三峡库区消落带微地貌扫描是监测库区消落带地表变形、揭示消落带波浪侵蚀过程的重要手段,随着摄影测量技术的进步,利用普通数码相机快速获取地形数据的近景摄影测量技术逐渐成熟。本研究利用普通单反相机获取三峡库区库岸研究区影像数据,利用近景摄影测量技术获取三维地形信息,并利用全站仪测量的验证点数据对结果进行精度验证。研究结果表明,利用本研究所使用的近景摄影测量技术可以在一定程度上还原地貌的三维信息,建立地面DEM模型,基本可以达到外业土壤侵蚀调查的要求,可以将该方法用于较粗略的三峡库区消落带土壤侵蚀参数的获取及土壤侵蚀过程的快速监测。 相似文献
4.
近年来,随着遥感技术的不断发展,利用遥感技术开展土地覆盖信息的提取工作已经变得越来越普遍。本文主要利用遥感技术进行土地覆盖信息的提取,为后续土地信息的分析调查提供了有利的数据。此次研究选取了渝西地区作为研究区,使用TM／ETM遥感图像作为基础数据。在提取覆盖信息之前,首先,采用遥感图像处理技术,对研究区进行了图像预处理;接着,对研究区四种地类进行采样处理,利用得到的采样数据,对研究区的遥感图像进行了光谱分析;最后,进行监督分类得到覆盖信息的明显特征,可以看出建筑用地在明显增多。并对分类结果进行精度评价,得到最后结论,可以看出每一时期的总分类精度都在85％以上,符合分类要求。 相似文献
5.
机载LiDAR和高光谱数据融合提取冰川雪线 总被引：1，自引：0，他引：1
以西藏那曲县境内的“中习一号”冰川为研究区,对2011年8月获取的机载激光雷达点云进行预处理和滤波分类,提取研究区数字高程模型(digital elevation model,DEM);将DEM数据分别与同期获取的机载高光谱栅格数据和提取出的冰川矢量数据进行三维地形模拟,利用DEM数据对高光谱最大似然法分类结果进行正射纠正,从而获取研究区的数字正射影像(digital orthophoto map,DOM);最后结合研究区DOM和机载点云数据提取“中习一号”冰川的雪线.结果表明:融合机载高光谱和机载激光雷达2种数据的优势,能更方便地提取出冰川雪线,而且能很好地显示雪线的高度. 相似文献
6.
基于SPOT 5和北京一号小卫星数据的北京北部山区土壤侵蚀变化研究 总被引：2，自引：0，他引：2
利用2004年10月SPOT 5卫星影像及2007年9月北京一号小卫星多光谱和全色影像,以植被覆盖度、坡度、土壤可蚀性和土地利用4种影响因子作为辅助数据,进行土壤侵蚀信息提取。利用所提取的信息,分析2004~2007年北京北部山区土壤侵蚀在空间、面积上的变化状况、强度类型转化状况以及变化的驱动力。分析结果表明,北京北部山区土壤侵蚀主要为轻度侵蚀与中度侵蚀,以轻度侵蚀为主; 2004~2007年北京北部山区虽然局部地区土壤侵蚀强度增强,但土壤侵蚀总面积减少,大体上呈中度→轻度→微度发展趋势,总体状况得到明显改善。 相似文献
7.
石漠化程度遥感信息提取方法研究 总被引：17，自引：0，他引：17
岩溶石漠化是中国西南地区的一种严重的生态环境问题。近年来有进一步恶化的趋势。本文以贵州省普定县典型研究区IKONOS遥感数据为例,给出了一种利用多光谱遥感数据定量提取岩溶石漠化程度信息的算法。在多维光谱的向量空间分析的基础上,提出了“植被线”的概念,并定义“石漠化几何指数”（GRI）为多维向量空间中不同程度的石漠化像元到“植被线”的归一化距离。作者认为使用这种方法提取石漠化程度,可以避免人工解译的主观性强,工作量大的缺点。使提取到的石漠化程度结果客观稳定。 相似文献
8.
油菜是我国主要的食用油料作物。及时、准确地获取油菜种植分布信息对油菜长势监测、估产以及灾情评估具有十分重要的意义。以江汉平原为研究区,利用250 m空间分辨率的MODIS EVI时序数据,以TM数据作为野外采样数据与MODIS EVI数据之间的过渡数据,间接提取MODIS EVI数据农作物的训练样本;通过分析江汉平原油菜和冬小麦的EVI光谱特征及物候信息,建立油菜种植面积提取模型;采用多次阈值比较法提取2014—2015年间江汉平原油菜种植分布信息。研究结果表明,2014年和2015年油菜面积遥感提取结果与农业局统计数据相比,总体提取精度分别达到95.22%和91.29%;2014年MODIS数据与TM数据提取的油菜面积一致性为88.61%;基于时间序列MODIS EVI数据,结合EVI光谱特征和物候信息,利用该方法可以有效提取江汉平原油菜种植分布信息。 相似文献
9.
10.
利用遥感影像准确地提取植被信息一直是遥感技术应用研究的重要内容,现提出基于支持向量机(SVM)分类的方法从ETM+多光谱数据中提取植被信息,利用目前常用的线性核函数、多项式核函数、径向基(RBF)核函数、Sigmoid核函数等四种核函数对研究区分别进行了提取研究,通过比较最终确定径向基函数(RBF)核函数有着最佳的提取效果。 相似文献
11.
长江上游小流域土壤侵蚀动态模拟与分析 总被引：1，自引：0，他引：1
以长江上游甘肃省尚沟流域为研究区,在遥感影像和GIS空间分析技术支撑下,根据USLE因子算法生成各因子栅格图,借助地图代数运算,估算了尚沟流域1998年和2004年的土壤侵蚀量,并对2004年土壤侵蚀与其环境背景因子进行叠加和空间统计分析。在此基础上,构建了与GIS软件平台集成的地理元胞自动机,模拟了该流域2004年、2010年和2020年土壤侵蚀空间演化情形。结果表明:研究区平均侵蚀量从1998年的6598.1t/km2下降到2004年的5923.3t/km2,侵蚀面积净减少172.3hm2,输沙量减少9.15×104t;1300～1400m的海拔高程带、25～35°坡度带、南坡和旱耕地是发生水土流失的主要区域;经模拟,2010年总侵蚀面积为93.49km2,侵蚀总量73.15×104t,侵蚀模数为5126t/km2,土壤侵蚀状况总体上将有所减缓。 相似文献
12.
Pramila Raina Mahesh Kumar Mohar Singh 《Journal of the Indian Society of Remote Sensing》2009,37(4):647-657
In the present study, efforts have been made to identify and map areas affected by various soil degradation processes in Hanumangarh
district of western Rajasthan. Soil degradation processes were identified by using IRS-1B satellite image of the year 1998,
SOI toposheets, ground truth verification and soil studies. The kind, extent and degree of soil degradation have been mapped
in an area of 9703 km2. The study reveals that the soil degradation problems were mainly due to wind erosion/deposition and water-logging, followed
by salinity/alkalinity, water erosion and wind and water erosion combinedly. Nearly 38.7% area is subjected to slight and
moderate degradation, which can easily be combated by adopting the suggested techniques and 17.1% area is free of hazard.
Soil degradation processes have resulted in the loss of organic carbon, available Phosphorus and Potassium. Soil degradation
due to water logging/salinization has also shown a significant increase in electrical conductivity and available potassium
content of soil. 相似文献
13.
14.
通过利用Terra/Aqua卫星上搭载的MODIS传感器计算获取的16d合成植被指数产品(MOD13A2),进一步按照最大值合成法计算月合成光谱植被指数,按照USLE模型月模式评价江西省2005年土壤侵蚀,并与传统的USLE模型年模式计算的结果进行了比较。 相似文献
15.
Pankaj Mani Rakesh Kumar C Chatterjee 《Journal of the Indian Society of Remote Sensing》2003,31(1):12-18
Majuli, the world’s largest river island, is situated in mid of river Brahmaputra in Assam. River Brahmaputra flows in highly
braided channels most of them are transient in nature, being submerged during high monsoon flows and changing drastically
their geometry and location. Majuli island, home of about 1.3 million people is endangered because of the erratic behavior
of the river. In this study, an attempt has been made to observe the trends of erosion in a small part of Majuli island, the
area near Kaniajan village in south Majuli- a stretch of about 11 km, using satellite data of 1991, 1997 and 1998. Image processing
of digital data has been done in ILWIS software. Supervised for delineation of river from land and then change detection analysis
has been done to find out changes in river course from 1991 to 1997 and further from 1997 to 1998. Erosion and deposition
maps of the area have been prepared and the erosion of island is measured at various sections at 1 km interval. Erosion of
1900 ha has been observed during the period of six years from 1991 to 1997 and 845 ha during the period of one year from 1997
to 1998. 相似文献
16.
Soil erosion is one of the major causes of land degradation in arid areas. Soil erosion models, e.g. the revised universal soil loss equation (RUSLE), use arithmetical expressions to explore relationships among various processes occurring in the terrain. The established model includes soil parameters, slope, climate and human activities to estimate the water erosion rate and sediment yield. In this study, an approach was adopted to integrate RUSLE model and geographic information system to detect erosion vulnerability and determine the soil erosion risk in the study area. The study area is situated in the Eastern Desert, Egypt. Ground truth data were examined to represent two regions: Luxor-Suhag and Suhag–ElMinya. These regions are exampled by four dry valleys named Sannor, Tarfa, Asyut and Qena, which are planned for agricultural development. The results indicate high risk of water erosion and sediment load discharge into the cultivated land in Luxor–Suhag region. The other region of Suhag–ElMinya is moderately affected by water and sediment load discharge. A higher soil erosion rate was found in Qena wadi followed by Asyut, then Tarfa and Sannur, respectively. 相似文献
17.
Pallavi Behera K. H. V. Durga Rao K. K. Das 《Journal of the Indian Society of Remote Sensing》2005,33(1):165-176
Hardly any part of the world has remained unchanged since the arrival of the speciesHomo sapiens including the mountain ecosystems. Himalayan physiographic unit of India in due course has become populated and is tolerating
all kinds of human interventions. Soil erosion in this region has been identified as a major problem due to both natural and
anthropogenic factors. Remote sensing and Geographical Information system (GIS) techniques hold great promises in the assessment
and conservation of natural resources including the surface soil. The major objective of the present study was to apply a
process based model to quantify soil erosion and to prioritize the sub-watershed on this basis. The sub-watershed located
at Jakhan rao area of Western Dun in lower Himalayan belt was taken as the test site for the study at 1: 50,000 scale. Deforestation,
unscientific agricultural practices, terrace farming, cattle grazing and land degradation in the sub-watershed are some of
the anthropogenic factors causing soil erosion in the area. Here, MMF model was used for estimation of soil erosion by incorporating
layers derived from both remote sensing and ancillary data. IRS 1C LISS III satellite data was used for the preparation of
land use map that was used to derive RD map, BD map and K map. Digital Elevation Model (DEM) provided slope map, an intermediate
layer used in equation 6 to generate G map, and soil map provided MS map, BD map and K map. The above intermediate layers
generated were then integrated in GIS domain to estimate the amount of soil erosion in the sub-watershed area. Results show
high values 4572.333 kg/m2 for G map, which depicted transport capacity of overland flow. Comparatively lower values 13.15, and 7.98 kg/m2were observed for F map, which depicted soil detachment by raindrop impact. The subtracted image of the aforesaid layers produced
the real picture, where in the highest value 3.770 kg/m2 was found in the midland region of the site. The crossed erosion map was then classified into different erosion classes for
sub-watershed area. This study illustrates the applications of remote sensing and GIS techniques for soil erosion modeling. 相似文献
18.
《地理信息系统科学与遥感》2013,50(4):388-410
Soil erosion is a prominent cause of land degradation and desertification in Mediterranean countries. The detrimental effects of soil erosion are exemplified in climate (in particular climate change), topography, human activities, and natural disasters. Forest fires, which are an integral part of Mediterranean ecosystems, are responsible for the destruction of above-and below-ground vegetation that protects against soil erosion. Under this perspective, the estimation of potential soil erosion, especially after fire events, is critical for identifying watersheds that require management to prevent sediment loss, flooding, and increased ecosystem degradation. The objective of this study was to model the potential post-fire soil erosion risk following a large and intensive wildland fire, in order to prioritize protection and management actions at the watershed level in a Mediterranean landscape. Burn severity and preand post-fire land cover/uses were mapped using an ASTER image acquired two years before the fire, air photos acquired shortly after the fire, and a Landsat TM image acquired within one month after-fire. We estimated pre-and post-fire sediment loss using an integrated GIS-based approach, and additionally we analyzed landscape erosion patterns. The overall accuracy of the severity map reached 83%. Severe and heavy potential erosion classes covered approximately 90% of the total area following the fire, compared to 55% before. The fire had a profound effect on the spatial erosion pattern by altering the distribution of the potential erosion classes in 21 out of 24 watersheds, and seven watersheds were identified as being the most vulnerable to post-fire soil erosion. The spatial pattern of the erosion process is important because landscape cover heterogeneity induced especially by fire is a dominant factor controlling runoff generation and erosion rate, and should be considered in post-fire erosion risk assessment. 相似文献
19.
缅甸中部干旱地区土壤侵蚀的分析 总被引：3，自引：0，他引：3
伊落瓦底江中游是缅甸中部著名的干热地带,地壤流失严重。在研究中,首先利用遥感图像（１９９５年的ＴＭ图像,１９９８年的ＴＭ和ＳＰＯＴ图像）进行判读和土壤侵蚀地面实况的野外验证。同时,根据影响封侵蚀的生态环境因子,建立实验区的数字高程模型和窨数据库。然后,在地理信息系统（ＧＩＳ）中进行土壤侵蚀测定以及生态环境因子相关分析。影响土壤侵镅的生态环境因子很多,但植被和耕作方式是人们可以控制的因子。在此基础上 相似文献
20.
安徽省大别山区江子河小流域的水文模拟与分析 总被引：1，自引：0，他引：1
目前,许多发达国家的研究已经证实,农业非点源污染是导致水环境恶化的主要原因之一。土壤侵蚀与非点源污染是一对密不可分的共生现象,特别在农业非点源污染中,土壤侵蚀是主要的发生形式,是一种重要的非点源污染。本文主要应用目前使用较广泛的非点源污染模型—SWAT模型对淮河流域安徽省大别山区水土流失较严重的江子河小流域进行径流量和泥沙量的模拟,并得到该小流域径流量和泥沙流失量的空间分布图。 相似文献