共查询到20条相似文献，搜索用时 687 毫秒
1.
The present study demonstrates the use of NRCS-CN technique for rainfall-induced run-off estimation using high-resolution satellite data for small watershed of Palamu district, Jharkhand. The CN model was applied to the daily rainfall data of 15 years (1986–2000) along with use of large-scale thematic maps (1:10,000) pertaining to land use/land cover using IRS-P6 LISS-IV satellite data. The LU/LC map was spatially intersected with the hydrological soil group map to calculate the watershed area under different hydrological similar units for assigning CN values to compute discharge. The study showed that Daltonganj watershed exhibits an average run-off volume of 7,881,019 m3 from an average cumulative monsoon rainfall of 821 mm and the average actual direct run-off generated during the southwest monsoon season was 203 mm. The strong correlation between rainfall and run-off as well as between observed run-off and estimated run-off indicated high accuracy of run-off estimation by NRCS-CN technique. 相似文献
2.
Using the global positioning system (GPS) for people tracking continues to get easier. A person can transmit his/her GPS location from the carried mobile devices. The location is usually displayed as a dot on a digital map. However, a dot on the map is insufficient to reveal the person’s actual situation, e.g., an accident being happening. If the GPS is incorporated with an IP (Internet Protocol) camera, the camera image is critical in revealing the person’s actual situation and to improve the above-mentioned insufficient information. We present an approach to facilitate such incorporation. The approach consists of three phases: locating, tracking and monitoring collision. When the GPS coordinates of a person are within the field-of-view (FOV) of a camera, the approach enters the locating phase. The GPS coordinates are transformed to specify a candidate area (CA) in the image. The update of GPS coordinates is used to filter those moving objects within the CA until only one remains. After the person is located, he is being tracked using the shortest Euclidean distance method to find the most likely object in the next image. If the person collides with other objects while being tracked, a template matching technique, the sum of absolute difference (SAD), is used to locate the person in the collision area. The tracking is done after the person leaves the FOV of the camera. In the experimental studies, the tracking of one to three persons was performed using the implemented prototype. The average locating error of the tracking phase is only 5 pixels. The highest and average tracking success rates are 95.9% and 90.6%, respectively. These results show that the proposed approach is accurate and feasible for people tracking by incorporating GPS and IP cameras. 相似文献
3.
Saptarshi Mondal Chockalingam Jeganathan 《Journal of the Indian Society of Remote Sensing》2018,46(12):2045-2055
Supervised multi-class classification (MCC) approach is widely being used for regional-level land use–land cover (LULC) mapping and monitoring. However, it becomes inefficient if the end user wants to map only one particular class. Therefore, an improved single-class classification (SCC) approach is required for quick and reliable map production purpose. In this regard, the current study attempts to evaluate the performance of MCC and SCC approaches for extracting mountain agriculture area using time-series normalized differential vegetation index (NDVI). At first, samples of eight LULC classes were acquired using Google Earth image, and corresponding temporal signatures (TS) were extracted from time-series NDVI to perform classification using minimum distance to mean (MDM) and spectral angle mapper (i.e., multi-class SAM—MCSAM) under MCC approach. Secondly, under SCC approach, the TS of three agriculture classes (i.e., agriculture, mixed agriculture and plantation) were utilized as a reference to extract agriculture extent using Euclidean distance (ED) and SAM (i.e., single-class SAM—SCSAM) algorithms. The area of all four maps (i.e., MDM—19.77% of total geographical area (TGA), MCSAM—21.07% of TGA, ED—15.23% of TGA, SCSAM—13.85% of TGA) was compared with reference agriculture area (14.54% of TGA) of global land cover product, and SCC-based maps were found to have close agreement. Also, the class-wise detection accuracy was evaluated using random sample point-based error matrix which reveals the better performance of ED-based map than rest three maps in terms of overall accuracy and kappa coefficient. 相似文献
4.
基于道路精简滤波原理的车辆导航系统地图匹配算法 总被引：1，自引：0，他引：1
针对交叉路口附近道路几何分布较为复杂的实际特点,提出基于道路精简滤波(RRF)原理的地图匹配算法。研究了基于D-S证据理论的多规则数据融合技术在二路段地图匹配中的应用。建立了最短欧氏距离和最小航向差两条判决规则。引入相关性模糊决策理论,将多路段匹配问题简化为二路段匹配问题,使D-S证据判决规则的概率分配函数能根据实际路网分布作适应性调整,提高了算法的鲁棒性。对实际跑车数据的仿真处理结果表明,应用该算法可以较好地解决城市交叉路口地图匹配问题。 相似文献
5.
道路网络背景下的距离度量（如道路网络距离、旅行时间）是在空间分析或空间统计过程中常用的距离度量,但在科研过程中由于道路数据的可获得性和精度等方面的限制,该类距离的计算可能较为困难。Minkowski距离函数是欧氏空间中的广义距离函数,其参数p值的不同代表着对空间不同的度量。利用Minkowski的通用性和灵活性（参数p不同的取值）,研究如何更好地逼近道路网络距离。同时,探索不同道路网络的部分计量特征（如密度、弯曲度等）与最优p值之间的关系。实验证明,相对于最常用的欧氏距离度量,优选p值后的Minkowski距离函数能够更大程度上逼近道路距离。而通过对道路网络计量特征与最优p值之间的关系的分析,指出了弯曲度与最优p值之间的对应关系,它对于p值的选择具有重要的指导意义。此外,为了验证Minkowski距离逼近算法的可行性,以地理加权回归分析为例,通过对比传统的欧氏距离度量、最优Minkowski距离度量和道路网络距离（旅行时间）对模型解算结果的影响,指出优选后Minkowski距离一定程度上更接近于采用旅行时间对模型解算的结果。 相似文献
6.
This study reports results from evaluation of the quality of digital elevation model (DEM) from four sources viz. topographic map (1:50,000), Shuttle Radar Topographic Mission (SRTM) (90 m), optical stereo pair from ASTER (15 m) and CARTOSAT (2.5 m) and their use in derivation of hydrological response units (HRUs) in Sitla Rao watershed (North India). The HRUs were derived using water storage capacity and slope to produce surface runoff zones. The DEMs were evaluated on elevation accuracy and representation of morphometric features. The DEM derived from optical stereo pairs (ASTER and CARTOSAT) provided higher vertical accuracies than the SRTM and topographic map-based DEM. The SRTM with a coarse resolution of 90 m provided vertical accuracy but better morphometry compared to topographic map. The HRU maps derived from the fine resolution DEM (ASTER and CARTOSAT) were more detailed but did not provide much advantage for hydrological studies at the scale of Sitla Rao watershed (5800 ha). 相似文献
7.
Masashi Miyagawa 《Journal of Geographical Systems》2012,14(2):209-222
This paper derives the joint distribution of the distances to the first and the second nearest points for regular and random
patterns. Distance is measured as the Euclidean and the rectilinear distances on a continuous plane. The joint distribution
extends the kth nearest distance distribution of previous works. The kth nearest distance distribution only shows how the distance to the kth nearest point is distributed, whereas the joint distribution provides the relationship between the distances. An application
of the joint distribution can be found in a facility location problem with non-closest facility service where the distance
to the second nearest facility is also important. The joint distribution that allows us to examine the first and the second
nearest distances simultaneously is useful for evaluating the reliability of facility location when some of the existing facilities
are closed. The joint distribution of the road network distances is also obtained to confirm that the model on a continuous
plane can be applied to actual road networks. 相似文献
8.
V. K. Pandey S. N. Panda N. S. Raghuwanshi S. Sudhakar 《Journal of the Indian Society of Remote Sensing》2006,34(2):143-152
Delineation of Banikdih Agricultural watershed in Eastern India was carried out and various watershed parameters were extracted
using Geographic Information System (GIS) and Remote Sensing. Digital Elevation Model (DEM) was developed with a contour interval
of 10 m in the scale of 1:25000 using ARC/INFO modules. Sub watershed, drainage, slope, aspect, flow direction, soil series,
soil texture, and soil class maps were independently generated and they were properly registered and integrated for analysis.
The watershed was digitally delineated using AVSWAT model that couples hydrological model and GIS with appropriate threshold
value of cell size. Subsequently, stream characteristics through the interface were generated. Indian Remote Sensing Satellite
IRS-1D LISS-III data pertaining to the period of October 29, 1998 and October 23, 2000 was used to develop land use/land cover
thematic map using ERDAS- 8.4 version image processing software. Eight major land use/land cover classes namely water body,
lowland paddy, upland paddy, fallow land, upland crop (non-paddy crops), settlement, open mixed forest, and wasteland were
segregated through digital image processing techniques using maximum likelihood algorithm. The information generated would
be of immense help in hydrological modeling of watershed for prediction of runoff and sediment yield, thereby providing necessary
inputs for developing suitable developmental management plans with sound scientific basis. 相似文献
9.
基于自组织神经网络的空间点群聚类及其应用分析 总被引：2，自引：0，他引：2
探讨了采用自组织神经网络进行离散空间点群聚类的原理、方法及应用分析,提出了一种兼顾几何距离和属性特征的广义Euclid距离,并将其作为聚类统计量.并以实例验证了采用自组织空间聚类进行空间点群的数据分类、异常数据检验、均质区域划分等是有效的. 相似文献
10.
This research analyses the suburban expansion in the metropolitan area of Tehran, Iran. A hybrid model consisting of logistic regression model, Markov chain (MC), and cellular automata (CA) was designed to improve the performance of the standard logistic regression model. Environmental and socio-economic variables dealing with urban sprawl were operationalised to create a probability surface of spatiotemporal states of built-up land use for the years 2006, 2016, and 2026. For validation, the model was evaluated by means of relative operating characteristic values for different sets of variables. The approach was calibrated for 2006 by cross comparing of actual and simulated land use maps. The achieved outcomes represent a match of 89% between simulated and actual maps of 2006, which was satisfactory to approve the calibration process. Thereafter, the calibrated hybrid approach was implemented for forthcoming years. Finally, future land use maps for 2016 and 2026 were predicted by means of this hybrid approach. The simulated maps illustrate a new wave of suburban development in the vicinity of Tehran at the western border of the metropolis during the next decades. 相似文献
11.
核密度估计法支持下的网络空间POI点可视化与分析 总被引：7，自引：0，他引：7
城市空间POI点的分布模式、分布密度在基础设施规划、城市空间分析中具有重要意义,表达该特征的核密度法(kernel density estimation)由于顾及了地理学第一定律的区位影响,比其他密度表达方法(如样方密度、基于Voronoi图密度)占优。然而,传统的核密度计算方法往往基于二维延展的欧氏空间,忽略了城市网络空间中设施点的服务功能及相互联系发生于网络路径距离而非欧氏距离的事实。本研究针对该缺陷,给出了网络空间核密度计算模型,分析了核密度方法在置入网络结构中受多种约束条件的扩展模式,讨论了衰减阈值及高度极值对核密度特征表达的影响。通过实际多种POI点分布模式(随机型、稀疏型、区域密集型、线状密集型)下的核密度分析试验,讨论了POI基础设施在城市区域中的分布特征、影响因素、服务功能。 相似文献
12.
由于影像间显著的几何和辐射差异,多源遥感影像自动匹配一直是目前研究的难点问题。首先引入具有光照和对比度不变性的相位一致性模型,并对其进行扩展,构建相位一致性的特征方向信息,然后借助于梯度方向直方图的模板结构,利用其特征值和特征方向,建立一种局部特征描述符——局部相位一致性方向直方图（local histogram of orientated phase congruency,LHOPC）,最后利用欧氏距离作为匹配测度进行同点名识别。对四组多源遥感影像进行试验,其结果表明,相比于尺度不变特征转换和加速鲁棒性特征算法,LHOPC能更为有效的抵抗影像间的辐射差异,提高了匹配性能。 相似文献
13.
超谱遥感图像快速聚类无损压缩算法 总被引：1，自引：0，他引：1
K-means聚类要求每个像素要和所有聚类中心求欧氏距离，当聚类数很多时，这是一个相当耗时的工作。改进的K—meam聚类算法根据历史聚类结果进行初始类分割，即节约初始聚类时间，又能使历史聚类过程中形成的类间稳定关系得以保持；类内像素只和相邻的聚类中心计算距离进行聚类，随着算法的迭代进行，大量类的状态基本固定，使得聚类速度不断加快。基于改进K-means聚类的无损压缩算法具有充分利用历史聚类成果和收敛速度快的特点，通过提高类内像素冗余度，最大限度消除谱间冗余和空间冗余。采用多次聚类压缩的结果预测最佳聚类数的方法，可实现最小熵无损压缩。通过和DPCM算法概率模型的熵值比较及实验数据的分析，验证了基于聚类无损压缩效率比不聚类无损压缩效果更优。 相似文献
14.
《International Journal of Digital Earth》2013,6(2):135-156
Abstract The Muthirapuzha watershed (MW) is one among the major tributaries of Periyar – the longest west flowing river in Kerala, India. A morphometric analysis was carried out to determine the spatial variations in the drainage characteristics of MW and its 14 fourth order sub-watersheds (SW1–SW14) using Survey of India topographic maps and Landsat ETM+ imagery. The study revealed that the watershed includes a sixth order stream and lower order streams dominate the basin. Results did indicate that rainfall has a significant role in the drainage development whereas structure and relief of rocks dictate the drainage pattern. The asymmetry in the drainage distribution is correlated with the tectonic history of the Munnar plateau in the late Paleocene age. The watershed is moderate to well-drained and exhibited a geomorphic maturity in its physiographic development. The shape parameters revealed the elongated nature of MW and drainage network development in the watershed. Further, the analysis provided significant insight into the terrain characteristics. This study strongly brings to light, (a) the tendency of the watershed to soil loss and (b) the hydrological makeup of the sub-watersheds, which combined helped to formulate a comprehensive watershed management plan. 相似文献
15.
光谱匹配分类方法以光谱相似性测度为分类准则,一种相似性测度只对应于光谱曲线的一种特征,用于光谱匹配分类效果并不好;组合不同类型的相似性测度能够有效改善分类效果,但光谱匹配分类往往忽略了相邻像元间的相关性。为了更好地利用空间信息,提高光谱匹配分类精度,首先组合欧氏距离测度和相关系数测度,得到欧氏距离-相关系数测度;其次通过加入空间乘子,得到结合空间信息的欧氏距离-相关系数测度,从而在光谱匹配分类中增加了空间信息约束。采用两组高光谱影像进行实验验证,结果表明,相比于单一相似性测度及组合相似性测度,结合空间信息的欧氏距离-相关系数测度用于光谱匹配分类能够有效改善分类精度。 相似文献
16.
Mahtab Safari Shad Mahmoud Habibnejad Roshan Alireza Ildoromi 《Journal of the Indian Society of Remote Sensing》2014,42(1):107-117
Because of the difficulty of monitoring and measuring snow cover in mountainous watersheds, satellite images are used as an alternative to mapping snow cover to replace the ground operations in the watershed. Snow cover is one of the most important data in simulation snowmelt runoff. The daily snow cover maps are received from Moderate Resolution Imaging Spectroradiometer (MODIS), and are used in deriving the snow depletion curve, which is one of the input parameters of the snowmelt runoff model (SRM). Simulating Snowmelt runoff is presented using SRM model as one of the major applications of satellite images processing and extracting snow cover in the Ghara - Chay watershed. The first results of modeling process show that MODIS snow covered area product can be used for simulation and forecast of snowmelt runoff in Ghara - Chay watershed. The studies found that the SCA results were more reliable in the study area. 相似文献
17.
18.
欧氏聚类算法是多元统计中的一种重要分类方法,可以将其应用于测绘领域中点云数据的分割。本文首先计算点云数据中两点之间的欧氏距离,将距离小于指定阈值作为分为一类的判定准则;然后迭代计算,直至所有的类间距大于指定阈值,完成欧氏聚类分割。具体步骤为：①利用Octree法建立点云数据拓扑组织结构;②对每个点进行k近邻搜索,计算该点与k个邻近点之间的欧氏距离,最小归为一类;③设置一定的阈值,对步骤②迭代计算,直至所有类与类之间的距离大于指定阈值。试验证明,欧氏聚类算法对不同测量技术手段获取的点云数据均具有适用性,可以成功对点云数据进行分割,分割效果良好。 相似文献
19.
P. K. Shrivastava M. P. Tripathi S. N. Das 《Journal of the Indian Society of Remote Sensing》2004,32(2):145-157
A distributed parameter model Soil and Water Assessment Tool (SWAT) has been tested on daily and monthly basis for estimating surface runoff and sediment yield from a small watershed “Chhokeranala” in eastern India using satellite data and Geographical Information System (GIS). Several maps like watershed and sub-watershed boundaries, drainage network, landuse/cover and soil texture have been generated. The SWAT model has been verified for the initial phase of monsoon season in the year 2002 using daily rainfall and air temperature. Performance of the model has been also evaluated to simulate the surface runoff and sediment yield on sub-watershed basis for two months (July-August 2002). The results show a good agreement between observed and simulated runoff and sediment yield during the study period. Capability of the model for generating rainfall has been evaluated for 10 years (1992 - 2001) period. The model simulated daily rainfall shows close agreement with the observed rainfall. The present results show that the SWAT model can be used for satisfactory simulation of daily and monthly rainfall, runoff and sediment yield. 相似文献
20.
《制图学和地理信息科学》2013,40(4):223-237
This paper presents a knowledge discovery approach to extracting knowledge from area–class resource maps. Prototype theory forms the basis of the approach which consists of two major components: (1) a scheme for organizing knowledge used in categorizing geographic entities which allows for the modeling of indeterminate boundaries and non–uniform memberships within categories; and (2) a data mining method using the Expectation Maximization (EM) algorithm for extracting such knowledge from area–class maps. A case study on knowledge discovery from a soil map demonstrates the details of the approach. The study shows that knowledge for classifying geographic entities with indeterminate boundaries is embedded in area–class maps and can be extracted through data mining; and that continuous spatial variation of geographic entities can be better modeled if the knowledge discovery process retains knowledge of within-class variations as well as transitions between classes. 相似文献