共查询到20条相似文献，搜索用时 15 毫秒
1.
自适应的IDW插值方法及其在气温场中的应用 总被引：3，自引：0，他引：3
反距离权重(Inverse Distance Weighting,IDW)插值通常采用距离搜索策略选择插值参考点,当采样点集分布不均匀时,距离搜索策略使得参考点聚集一侧影响插值精度。自然邻近关系具有良好的自适应分布特性,可有效地解决参考点分布不均匀问题。结合自然邻近关系,提出自适应的反距离权重(Adaptive-IDW,AIDW)插值方法。首先对采样数据构建初始Delaunay三角网,然后采用逐点插入法,将待插值点插入初始Delaunay三角网中,局部调整得到新的Delaunay三角网,以待插值点的一阶邻近点作为IDW插值的参考点,使参考点自适应均匀地分布在待插值点周围,再进行IDW插值计算。利用AIDW插值方法对Franke函数、全国气温观测数据进行插值实验,结果表明此方法具有较高的精度,且减少了“牛眼”现象。 相似文献
2.
Surface modeling of DEMs based on a sequential adjustment method 总被引：1，自引：0，他引：1
Chuanfa Chen Yanyan Li Tianxiang Yue 《International journal of geographical information science》2013,27(7):1272-1291
A sequential adjustment (SA) method is employed to decrease the computational cost of high-accuracy surface modeling (HASM), and the SA of HASM (HASM-SA) is being developed. A mathematical surface was used to comparatively analyze the computing speed of SA and the classical iterative solvers provided by MATLAB 7.7 for solving the system of linear equations of HASM. Results indicate that SA is much faster than the classical iterative solvers. The computing time of HASM-SA is determined by not only the total number of grid cells but also the number of sampling points in the computational domain. A real-world example of surface modeling of digital elevation models (DEMs) with various resolutions shows that HASM-SA is averagely more accurate and much faster than the commonly used interpolation methods, such as inverse distance weighting (IDW), kriging, and three versions of spline, namely regularized spline (RSpline), thin-plate spline (TPS), and ANUDEM in terms of root mean square error (RMSE), mean absolute error (MAE), and mean error (ME). In particular, the ME of HASM-SA at different spatial resolutions is averagely smaller than those of IDW, kriging, RSpline, TPS, and ANUDEM by 85%, 83%, 83%, 53%, and 19%, respectively. The high speed and high accuracy of HASM-SA can be due to the absence of matrix inversion computation, combined with the perfect fundamental theorem of HASM. 相似文献
3.
We developed a method for high-accuracy surface modeling (HASM) in terms of the fundamental theorem of surfaces, which has theoretically found a solution for error problems. However, the computing speed of HASM was too slow to be widely applied in practice. Thus, adjustment computation of HASM (HASM-AC) is developed in this article. For comparatively testing HASM-AC accuracy, a mathematical surface is first selected so that the true value is able to be predetermined to avoid uncontrollable data errors. The numerical test indicates that HASM-AC has the highest accuracy and its accuracy is 20.67, 15.67, and 14.67 times higher than the inverse distance weighting (IDW), kriging, and spline, respectively. Then, a 0.4 km × 0.5 km rectangular area is used to test the effects of different spatial resolutions and sampling intervals on accuracy. This real-world test demonstrates that HASM-AC accuracy increases at a much better and stable pace as the spatial resolution becomes finer and sampling intervals get shorter, compared to the classic methods. Finally, the computing speed is tested in an area with 6000 × 6000 grid cells where Qinghai, Gansu, and Sichuan provinces meet. The computing speed of HASM-AC is 11, 8, and 563 times faster than IDW, spline, and kriging, respectively, which makes HASM-AC able to process data in a huge size and make real-time visualization realizable. In short, HASM-AC performs best in both the numerical and real-world tests. 相似文献
4.
对不同的地貌区进行空间内插时选择的适宜方法不同,以典型丘陵地貌区长春市净月潭地区的高程为研究对象,用ArcGIS 9.2分别作反距离权重法、最近邻点法、趋势面分析和克里金法做高程内插。应用交叉检验方法对其内插的精度作出分析,检验其科学性和可靠性,得出反距离权重法、最近邻点法、趋势面法、样条函数法和克里金法高程内插的不同精度,并对各种方法的适用性进行讨论。结果表明最近邻点法精度最高,以下依次为普通克里金插值法、样条函数、反距离权重法、趋势面法。为类似于净月潭地区的丘陵地貌区高程内插提供选择参考。 相似文献
5.
为探索不同空间插值方法得到的DEM如何影响土壤侵蚀模拟效果,本文选择金沙江干热河谷区典型冲沟为研究对象,利用野外测量高程数据,采用反距离加权(IDW)、析取克里格(DK)、局部多项式(LPI)和张力样条函数(ST)4种方法构建高精度DEM。基于USPED模型模拟冲沟的土壤侵蚀,对比不同空间插值方法的精度、土壤侵蚀的空间分布,采用相对差系数对比不同插值在土壤侵蚀研究中的相似性。结果表明：DEM空间插值的精度排序为ST相似文献
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7.
癌症已成为危害全球居民健康的重大民生问题,选取合适的空间插值方法分析小区域癌症数据的空间特征可对区域性癌症防控工作的有效开展提供依据。本研究以湖南省苏仙区2012和2016年以村为单位的肺癌死亡率数据为研究对象,以平均误差和均方根误差为评价指标,对反距离加权（IDW）、普通克里金（OK）、趋势面分析（TSA）、多元线性回归（MLR）与协同克里金（CK）五种典型空间插值方法进行精度效果对比及参数优选,并结合不同插值方法的优缺点,确定癌症数据的最优插值方法。结果表明：插值精度方面,CK法的均方根误差最小、插值精度最高,OK、IDW（幂值=1）和MLR次之,TSA（阶数=5）最低;插值效果方面,五种插值方法的实测值和预测值均显著相关,除CK外,其它四种方法均对死亡率低估程度较大,CK和OK插值结果的空间分布效果更好。同时考虑空间因素和影响因子的CK方法是小区域苏仙区2012年、2016年肺癌死亡率最优插值方法,应用该方法可对区域性癌症防控工作的有效开展提供最优的技术支撑。本论文的研究思路也可为小区域癌症数据空间插值方法及参数优选提供参考。 相似文献
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9.
Christopher D. Lloyd Peter M. Atkinson 《International journal of geographical information science》2013,27(5):535-563
This paper focuses on two common problems encountered when using Light Detection And Ranging (LiDAR) data to derive digital elevation models (DEMs). Firstly, LiDAR measurements are obtained in an irregular configuration and on a point, rather than a pixel, basis. There is usually a need to interpolate from these point data to a regular grid so it is necessary to identify the approaches that make best use of the sample data to derive the most accurate DEM possible. Secondly, raw LiDAR data contain information on above‐surface features such as vegetation and buildings. It is often the desire to (digitally) remove these features and predict the surface elevations beneath them, thereby obtaining a DEM that does not contain any above‐surface features. This paper explores the use of geostatistical approaches for prediction in this situation. The approaches used are inverse distance weighting (IDW), ordinary kriging (OK) and kriging with a trend model (KT). It is concluded that, for the case studies presented, OK offers greater accuracy of prediction than IDW while KT demonstrates benefits over OK. The absolute differences are not large, but to make the most of the high quality LiDAR data KT seems the most appropriate technique in this case. 相似文献
10.
基于GIS的新疆气温数据栅格化方法研究 总被引：1，自引：1，他引：0
以新疆99个气象台站1971-2010年年平均气温为数据源,采用多元回归结合空间插值的方法对新疆区域气温数据进行栅格化研究。建立了年平均气温与台站经纬度和海拔高度的多元回归模型,对于残差数据的插值采用了反距离权重法(IDW) 、普通克立格法 (Kriging)和样条函数法(Spline)3种目前应用广泛的空间插值方法,针对于这3种方法进行了基于MAE和RMSIE的交叉验证和对比分析,结果表明在新疆的年平均气温的GIS插值方案中,IDW方法精度总体要高于其他两种插值方法。 相似文献
11.
环渤海地区海洋经济增长质量空间溢出效应研究 总被引：4，自引：2，他引：2
海洋经济向质量效益型转变是建设海洋强国的新要求。通过构建海洋经济?地理距离空间权重矩阵对2000—2014年环渤海地区17个沿海地级市海洋经济增长质量主体的空间交互作用及空间效应进行研究;借助空间计量模型对海洋经济增长质量空间效应影响因素进行甄别。研究表明：① 环渤海地区海洋经济增长质量主体呈显著空间相关性,存在空间交互作用;② 海洋经济增长质量存在空间溢出的正反馈效应。影响因素中对环渤海地区海洋经济增长质量的直接贡献强度排序为：海洋环境>海洋产业>海洋人才>海洋资本>海洋科技,对其他地区溢出效应影响的排序为：海洋基建>海洋人才>海洋资本。研究为环渤海地区海洋政策制定提供一定参考依据。 相似文献
12.
气象要素空间插值方法优化 总被引：86，自引：8，他引：78
在区域水土平衡模型的研究中 ,空间插值可提供每个计算栅格的气象要素资料。本文运用反距离加权法 (IDW )和梯度距离反比法 (GIDW ) ,对 196 1～ 2 0 0 0年甘肃省及其周围85个气象站点的多年平均温度与降雨量进行了内插。交叉验证结果表明 :对于IDW和GIDW ,二者温度插值的平均绝对误差 (MAE)分别为 2 2 8℃和 0 73℃ ,平均相对误差(MRE)分别为 2 9 0 2 %和 9 4 1% ,降雨插值的MAE值依次为 5 5 2mm和 4 90mm ,MRE值分别为 19 4 3%和 17 80 % ,GIDW明显优于IDW。需要指出的是 :对于降雨 ,当其经纬度和海拔高程的复相关系数大于 0 80时 ,GIDW插值结果优于IDW ;否则相反 相似文献
13.
Jun Zhang Kyriakos Mouratidis Zhu Manli 《International journal of geographical information science》2013,27(10):1091-1111
Despite the existence of obstacles in many database applications, traditional spatial query processing assumes that points in space are directly reachable and utilizes the Euclidean distance metric. In this paper, we study spatial queries in the presence of obstacles, where the obstructed distance between two points is defined as the length of the shortest path that connects them without crossing any obstacles. We propose efficient algorithms for the most important query types, namely, range search, nearest neighbours, e‐distance joins, closest pairs and distance semi‐joins, assuming that both data objects and obstacles are indexed by R‐trees. The effectiveness of the proposed solutions is verified through extensive experiments. 相似文献
14.
借助反距离权重(IDW)空间插值及空间相关分析方法,对贵州省县域经济发展的空间分异特征及自然环境因素与县域经济发展的相关程度及限制作用进行分析。结果表明,贵州省县域经济发展水平在空间上存在较大差异,经济发展水平较高区域主要分布于贵阳、遵义、凯里、铜仁、都匀、兴义等政府所在地,其他县(市)人均GDP水平相对较低;经济发展水平与环境限制因子相关程度各异,其中六盘水、安顺及贵阳地区经济发展水平与环境限制因子关系密切,其他地区相关程度不明显。 相似文献
15.
Ferenc Csillag Miklós Kertész Ágnes Kummert 《International journal of geographical information science》2013,27(7):851-875
Abstract Mapping by sampling and prediction of local and regional values of two-dimensional surfaces is a frequent, complex task in geographical information systems. This article describes a method for the approximation of two-dimensional surfaces by optimizing sample size, arrangement and prediction accuracy simultaneously. First, a grid of an ancillary data set is approximated by a quadtree to determine a predefined number of homogeneous mapping units. This approximation is optimal in the sense of minimizing Kullback-divergence between the quadtree and the grid of ancillary data. Then, samples are taken from each mapping unit. The performance of this sampling has been tested against other sampling strategies (regular and random) and found to be superior in reconstructing the grid using three interpolation techniques (inverse squared Euclidean distance, kriging, and Thiessen-polygonization). Finally, the discrepancy between the ancillary grid and the surface to be mapped is modelled by different levels and spatial structures of noise. Conceptually this method is advantageous in cases when sampling strata cannot be well defined a priori and the spatial structure of the phenomenon to be mapped is not known, but ancillary information (e.g., remotely-sensed data), corresponding to its spatial pattern, is available. 相似文献
16.
利用空间插值法估算云覆盖像元地表温度的可行性研究 总被引：1，自引：0，他引：1
云覆盖是热红外遥感应用和地表温度遥感定量反演的重要障碍。实验选取河北衡水地区Landsat TM影像,借助GIS的空间分析功能,探索运用反距离加权(IDW)和普通克里金插值(OK)方法近似估算3种典型地表类型(水面、城镇、农田)下的云覆盖像元地表温度的可行性。实验结果显示:当云覆盖区域达15 000个像元(约等于13.5km2)时,两种空间插值方法对城镇的云覆盖像元地表温度估算误差都为1.6°C左右,而农田和水面的估算误差在1°C左右(且水面估算误差小于农田),这与3种典型地表类型的地表温度空间异质性密切相关。因此,当Landsat TM图像中有少块云覆盖而发生地表温度值缺失时,利用空间插值法估算云覆盖像元的地表温度是切实可行的。 相似文献
17.
Steve W. Lyon Rasmus S⊘rensen Johan Stendahl Jan Seibert 《International journal of geographical information science》2013,27(5):723-740
Interpolation of point measurements using geostatistical techniques such as kriging can be used to estimate values at non-sampled locations in space. Traditional geostatistics are based on the spatial autocorrelation concept that nearby things are more related than distant things. In this study, additional information was used to modify the traditional Euclidean concept of distance into an adjusted distance metric that incorporates similarity in terms of quantifiable landscape characteristics such as topography or land use. This new approach was tested by interpolating soil moisture content, pH and carbon-to-nitrogen (C:N) ratio measured in both the mineral and the organic soil layers at a field site in central Sweden. Semivariograms were created using both the traditional distance metrics and the proposed adjusted distance metrics to carry out ordinary kriging (OK) interpolations between sampling points. In addition, kriging with external drift (KED) was used to interpolate soil properties to evaluate the ability of the adjusted distance metric to incorporate secondary data into interpolations. The new adjusted distance metric typically lowered the nugget associated with the semivariogram, thereby better representing small-scale variability in the measured data compared to semivariograms based on the traditional distance metric. The pattern of the resulting kriging interpolations using KED and OK based on the adjusted distance metric were similar because they represented secondary data and, thus, enhanced small-scale variability compared to traditional distance OK. This created interpolations that agreed better with what is expected for the real-world spatial variation of the measured properties. Based on cross-validation error, OK interpolations using the adjusted distance metric better fit observed data than either OK interpolations using traditional distance or KED. 相似文献
18.
Amy Hessl Jennifer Miller James Kernan David Keenum Don McKenzie 《The Professional geographer》2007,59(1):87-104
Fire history studies have traditionally emphasized temporal rather than spatial properties of paleo‐fire regimes. In this study we compare four methods of mapping paleo‐fires in central Washington from binary point data: indicator kriging, inverse distance weighting, Thiessen polygons, and an expert approach. We evaluate the results of each mapping method using a test (validation) dataset and receiver operating characteristic plots. Interpolation methods perform well, but results vary with fire size and spatial pattern of points. Though all methods involve some subjectivity, automated interpolation methods perform well, are replicable, and can be applied across varying landscapes. 相似文献
19.
面向离散点的空间权重矩阵生成算法与实证研究 总被引：2，自引：0，他引：2
采用阈值法和k-近邻法度量空间上离散点间的空间邻接关系,针对不同的距离计算方式(欧式距离和曼哈顿距离)设计了面向离散点的空间权重矩阵生成算法,使用C#语言在计算机上实现。用该算法对收集的8 367个常州市地价样点构建了不同土地用途地价样点的空间权重矩阵,并计算出分用途的常州市城市地价空间自相关指数。 相似文献
20.
G. B.M. Heuvelink Z. Jiang S. De Bruin C. J.W. Twenhöfel 《International journal of geographical information science》2013,27(3):365-382
In case of a nuclear accident, decision makers rely on high-resolution and accurate information about the spatial distribution of radioactive contamination surrounding the accident site. However, the static nuclear monitoring networks of many European countries are generally too coarse to provide the desired level of spatial accuracy. In the Netherlands, authorities are considering a strategy in which measurement density is increased during an emergency using complementary mobile measuring devices. This raises the question, where should these mobile devices be placed? This article proposes a geostatistical methodology to optimize the allocation of mobile measurement devices, such that the expected weighted sum of false-positive and false-negative areas (i.e. false classification into safe and unsafe zones) is minimized. Radioactivity concentration is modelled as the sum of a deterministic trend and a zero-mean spatially correlated stochastic residual. The trend is defined as the outcome of a physical atmospheric dispersion model, NPK-PUFF. The residual is characterized by a semivariogram of differences between the outputs of various NPK-PUFF model runs, designed to reflect the effect of uncertainty in NPK-PUFF meteorological inputs (e.g. wind speed, wind direction). Spatial simulated annealing is used to obtain the optimal monitoring design, in which accessibility of sampling sites (e.g. distance to roads) is also considered. Although the methodology is computationally demanding, results are promising and the computational load may be considerably reduced to compute optimal mobile monitoring designs in nearly real time. 相似文献