高分辨率遥感图像最近邻模糊分类器的研究及实现     

朱国龙  汪云甲  乔浩然  刘乐乐  赵一清 《测绘科学》2010,35(6):96-98

本文针对高分辨率遥感影像快速高效萃取有用信息这一遥感技术应用的热点问题,探讨了一种适合于组合特征识别的遥感图像最近邻模糊分类器。该分类器首先把待识别目标的组合特征与训练模板中的组合特征样本的平均值一一进行比较,从而得到了一个特征差矩阵。用模糊分布函数在同类特征差之间进行处理,生成一个隶属度矩阵,然后用算术平均法对隶属度矩阵进行处理,并用最大隶属度准则来进行分类判决。以新疆和静县的SPOT5图像为例,应用此方法对其进行分类试验。结果表明:利用此分类方法对SPOT5遥感图像进行分类,不仅使分类结果具有丰富的语义信息,而且克服了由于特征选择的不稳定性对分类结果的影响,分类精度也得到了显著的提高。  相似文献   

模糊地理实体不确定性综合描述研究   总被引：2，自引：0，他引：2  

郭继发  崔伟宏  刘臻  彭光雄 《武汉大学学报(信息科学版)》2010,(1)

从二型模糊的角度讨论了模糊地理实体的不确定性,基于空间数据的位置误差,利用模糊集的λ-截集和圆误差带模型推导了模糊地理实体隶属度的误差模型,并给出了隶属度不确定性的度量方法,提出了用隶属度误差立方体来综合描述模糊点的不确定性。  相似文献   

Evolution of scouring process downstream of grade‐control structures under steady and unsteady flows     

Jau‐Yau Lu  Jian‐Hao Hong  Kai‐Po Chang  Tai‐Fang Lu 《水文研究》2013,27(19):2699-2709

For many incised channels, one of the most common strategies is to install some hard structures, such as grade‐control structures (GCSs), in the riverbed to resist further incision. In this study, a series of experiments, including both steady and unsteady flow conditions, were conducted to investigate the scouring process downstream of a GCS. Three distinct phases, including the initial, developing and equilibrium phases, during the evolution of scour holes were identified. In addition, a semi‐empirical method was proposed to predict the equilibrium scour‐hole profile for the scour countermeasure design. In general, the comparisons between the experimental and simulated results are reasonably consistent. As the studies on temporal variation of the scour depth at GCSs caused by floods are limited, the effect of flood hydrograph shapes on the scour downstream of GCSs without upstream sediment supply was also investigated experimentally in this study. Based on the dimensional analysis and the concept of superposition, a methodology is proposed to simulate the time evolution of the maximum scour depth downstream of a GCS for steady flows. Moreover, the proposed scheme predicts reasonably well the temporal variations of the maximum scour depth for unsteady flows with both single and multiple peak. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

关中平原清代霜雪灾害特点与周期研究     

赵景波  陈颖  周旗 《地球科学与环境学报》2012,(3):75-82

通过对关中平原清代历史文献资料的搜集、整理和小波分析,对该区清代霜雪灾害等级、周期及其成因进行了研究,并恢复了该区清代霜雪灾害发生时的最低气温.结果表明:关中平原清代共发生霜雪灾害34次,其中轻度、中度、重度霜雪灾害分别为2、20、12次;关中平原清代霜雪灾害可分为3个阶段,1644~1733年为第1阶段,1734~1823年为第2阶段,1824~1912年为第3阶段;第1和第3阶段为霜雪灾害多发阶段,以中度和重度灾害为主,第2阶段为霜雪灾害少发阶段,以轻度和中度灾害为主;小波分析表明,关中平原清代霜雪灾害的发生存在不同的时间周期规律,其周期主要有9~15年、13年、34年左右和40年左右;降雪或寒流引起的气温骤降至0℃以下是造成关中平原清代霜雪灾害的主要原因;关中平原清代轻度和中度霜雪灾害的气温范围为-6.4℃~-1℃,重度的气温范围一般为-19℃~-17℃;关中平原清代共发生3次寒冷气候事件,分别为1690~1692年、1861~1865年和1893~1895年.  相似文献   

Quantification of spatial gradation of slope positions   总被引：6，自引：0，他引：6  

Cheng-Zhi Qin  A-Xing Zhu  Xun Shi  Bao-Lin Li  Tao Pei  Cheng-Hu Zhou 《Geomorphology》2009,110(3-4):152-161

Transition between slope positions (e.g., ridge, shoulder slope, back slope, foot slope, and valley) is often gradual. Quantification of spatial transitions or spatial gradations between slope positions can increase the accuracy of terrain parameterization for geographical or ecological modeling, especially for digital soil mapping at a fine scale. Current models for characterizing the spatial gradation of slope positions based on a gridded DEM either focus solely on the parameter space or depend on too many rules defined by topographic attributes, which makes such approaches impractical. The typical locations of a slope position contain the characteristics of the slope position in both parameter space and spatial context. Thus, the spatial gradation of slope positions can be quantified by comparing terrain characteristics (spatial and parametrical) of given locations to those at typical locations. Based on this idea, this paper proposes an approach to quantifying the spatial gradation of slope positions by using typical locations as prototypes. This approach includes two parts: the first is to extract the typical locations of each slope position and treat them as the prototypes of this position; and the second is to compute the similarity between a given location and the prototypes based on both local topographic attributes and spatial context. The new approach characterizes slope position gradation in both the attribute domain (i.e., parameter space) and the spatial domain (i.e., geographic space) in an easy and practicable way. Applications show that the new approach can quantitatively describe spatial gradations among a set of slope positions. Comparison of spatial gradation of A-horizon sand percentages with the quantified spatial gradation of slope positions indicates that the latter reflects slope processes, confirming the effectiveness of the approach. The comparison of a soil subgroup map of the study area with the maximum similarity map derived from the approach also suggests that the quantified spatial gradation of slope position can be used to aid geographical modeling such as digital soil mapping.  相似文献   

新疆旅游资源的类型、等级及空间分布特征   总被引：5，自引：3，他引：2  

王燕  阎顺  赵彩龙 《干旱区地理》2009,32(5)

在全面掌握新疆旅游资源的实查资料基础上,对全疆旅游资源做系统分类与定量评价,总结其类型、等级和空间分布特征,并从新疆地理环境变迁和多民族、多文化的社会环境两方面分析新疆高品质旅游资源的成因。结果表明:新疆旅游资源类型多样,与全国相比,主类、亚类齐全,基本类型占66.5%;八大类中建筑与设施和地文景观的种类较丰富;建筑与设施类景点最多,水域风光和生物景观次之;新疆旅游资源等级较高,优良级占43.6%,整体为中间大两头小的谷仓型结构;高等级集中于凸峰、观光游憩湖区、林地、草地、野生动物栖息地、废城与聚落地、石窟、边境口岸、特色街巷、传统手工产品与制品、民间演艺等类;空间分布呈现为三带两环状和六点状集聚特征,这与新疆地貌格局和高品质景点的聚群作用有关;新疆自然旅游资源是整个地理环境演变过程的产物;而多民族、多文化的社会环境是人文类的主要成因。  相似文献   

基于文献记录的黑河流域历史时期旱涝特征分析   总被引：1，自引：0，他引：1  

唐霞  张志强 《冰川冻土》2017,39(3):490-497

流域的旱涝灾害特征及其变化规律是流域水资源演变研究的重要内容。利用历史文献资料重建了西北内陆河黑河流域公元0-1949年的旱涝灾害等级序列,结合滑动平均、小波变换处理等方法,探讨了流域历史时期旱涝等级的频数特征、旱涝变化的周期特征及其与气候冷暖和人类活动之间的关系。对公元1000年以后的旱涝灾害规律进行分析,结果表明：流域存在5个旱灾高发阶段（1230-1270年、1430-1530年、1640-1760年、1860-1890年、1900-1940年）,3个涝灾高发期（1650-1690年、1730-1790年、1830-1910年）,并呈现出旱涝灾害频发的态势;1000-1949年期间,流域旱涝灾害存在4个准周期变化,对比发现这与太阳黑子活动等环境变化周期有紧密的联系;1580年以前,气候冷暖是影响旱涝灾害发生的主要因子,但16世纪以后,旱涝灾害交替频发,很可能是人类活动加剧了该现象。所以,定量辨析自然因素和人类活动对流域旱涝灾害的影响将是未来研究的重点方向。  相似文献   

能坡法流量实时在线自动监测系统在沈丘水文站的应用          下载免费PDF全文

韩新庆 《水文》2017,37(1):79-82

能坡法流量实时在线自动监测系统结合计算机处理、网络数据传输等先进技术,可以将常规的水文要素监测方式转变为信息采集、存贮、传输运用为一体的自动化、数字化过程。通过该系统在沈丘水文站的应用,与流速仪法测流进行对比分析,从而验证了能坡法流量实时在线自动监测系统的可靠性与合理性。  相似文献   

Modeling uncertainty in the three-dimensional structural deformation and stratigraphic evolution from outcrop data: Implications for submarine channel knickpoint recognition     

《Marine and Petroleum Geology》2017

Digital outcrop models help to constrain the interactions of stratigraphic and structural heterogeneity on ancient depositional systems. This study uses a stochastic approach that incorporates stratigraphic and structural modeling to interrogate the three-dimensional morphology of deep-water channel strata outcropping on Sierra del Toro in the Magallanes Basin of Chile. This approach considers the relative contributions, and associated uncertainty, of erosional downcutting versus post-depositional structural folding and small-offset faulting on the present-day configuration of the submarine channel complexes. Paleodepositional channel-belt gradients were modeled using a combination of three-dimensional visualization, stochastic surface modeling, palinspastic restoration, and decompaction modeling that are bound with errors constrained by stratigraphic and structural uncertainty. Modeling results indicate that at least 100 m of downcutting occurs over 6 km, and the resultant thalweg gradient of 64–125 m/km (decompacted) suggests that the Cerro Toro axial channel belt is an out-of-grade depositional system. Furthermore, the presence of steeper segments (100–175 m/km decompacted) suggests the preservation of one or more knickpoints that are similar in magnitude to tectonically-induced knickpoints on the modern seafloor. The interpreted knickpoints are correlated with a decreasing channel width-depth ratio and an increase of channel depth. These results indicate that stochastic surface modeling using digital outcrop models can constrain stratigraphic interpretations and post-depositional structural heterogeneity.  相似文献   

山东招远平度断裂破碎带蚀变岩型矿石类型划分          下载免费PDF全文

刘四川  孙忠实  杨永强  孙黎  范思琦  徐裴裴  定立 《山东国土资源》2012,28(3):9-11

山东招远-平度断裂破碎带蚀变岩型部分矿石类型划分与实际生产工作相脱离,该文在前人分类的基础上,提出新的定名方案,将矿石类型初步划分为含金蚀变花岗岩、含金黄铁绢英岩、含金硅化黄铁绢英岩、含金硅化岩、含金硅质石英脉和细脉含金硫化物。该划分方案使每一种矿石类型与金品位高低和SiO2含量的多少相联系,并作为找矿标志,操作性强,有利于矿山生产,加快了探矿进度。  相似文献