Applying essentially non‐oscillatory interpolation to controlled‐source electromagnetic modelling*     

M. Wirianto  W.A. Mulder  E.C. Slob 《Geophysical Prospecting》2011,59(1):161-175

Modelling and inversion of controlled‐source electromagnetic (CSEM) fields requires accurate interpolation of modelled results near strong resistivity contrasts. There, simple linear interpolation may produce large errors, whereas higher‐order interpolation may lead to oscillatory behaviour in the interpolated result. We propose to use the essentially non‐oscillatory, piecewise polynomial interpolation scheme designed for piecewise smooth functions that contains discontinuities in the function itself or in its first or higher derivatives. The scheme uses a non‐linear adaptive algorithm to select a set of interpolation points that represent the smoothest part of the function among the sets of neighbouring points. We present numerical examples to demonstrate the usefulness of the scheme. The first example shows that the essentially non‐oscillatory interpolation (ENO) scheme better captures an isolated discontinuity. In the second example, we consider the case of sampling the electric field computed by a finite‐volume CSEM code at a receiver location. In this example, the ENO interpolation performs quite well. However, the overall error is dominated by the discretization error. The other examples consider the comparison between sampling with essentially non‐oscillatory interpolation and existing interpolation schemes. In these examples, essentially non‐oscillatory interpolation provides more accurate results than standard interpolation, especially near discontinuities.  相似文献   

核密度估计的道路匹配方法探讨     

邹丹  毛政元  李继红  刘小伶 《测绘科学》2015,40(7):104-108

针对目前地图合并技术的同名实体匹配中线实体(以道路为例)研究的不足,文章基于密度插值和DEM分析,提出一种针对线实体进行全局匹配的方法:采用积分的思想将核密度估计方法扩展应用于线实体密度计算,通过提取其密度谷脊线,将其应用于地图合并技术领域中的线实体匹配研究主题,指导相似度指标阈值的选取,并取得了较好的效果,为实现同一地区不同来源或不同比例尺(主要是相近比例尺)地图数据合并及数据库集成提供了参考。  相似文献   

空间插值算法在GIS中的应用   总被引：2，自引：0，他引：2  

张子昕  周强波 《测绘与空间地理信息》2015,(2):103-107

在GIS的研究中,通常需要具有一定规则的数据,而多数可获得的数据都是呈现离散状态并且是不规则分布的,这就需要应用空间插值的方法把离散的不规则数据转换成规则数据.本文介绍了几种常用的空间插值模型的原理与方法,并通过规则格网DEM的建立,说明空间插值算法在GIS中的应用.  相似文献   

GPS精密星历的轨道内插方法比较   总被引：3，自引：1，他引：2  

王磊  罗年学 《地理空间信息》2009,7(5):113-116

在高精度的GPS测量数据处理过程中，获取高精度卫星轨道是重要的环节，内插是获取任意历元的精密轨道信息的重要手段，对拉格朗日插值法、牛顿插值法、Neville逐次线性内插法和切比雪夫插值法的效果做了细致的比较，并在此基础上进一步探讨了短时间外推的效果。  相似文献   

Mapping radar-derived sea surface currents with a variational method   总被引：1，自引：0，他引：1  

Max Yaremchuk  Alexei Sentchev 《Continental Shelf Research》2009,29(14):1711-1722

High-frequency radars measure projections of surface velocity vectors on the directions of the radar beams. A variational method for reconstruction of the 2d velocity field from such observations is proposed. The interpolation problem is regularized by penalizing high-frequency variability of the surface vorticity and divergence fields. Twin-data experiments are used to assess the method's skill and compare it with two well-known approaches to HFR data processing: conventional local interpolation and more sophisticated non-local scheme known as open-boundary modal analysis (OMA). It is shown that the variational method and OMA have a significant advantage over local interpolation because of their ability to reconstruct the velocity field within the gaps in data coverage, near the coastlines and in the areas covered only by one radar. Compared to OMA, the proposed variational method appears to be more flexible in processing gappy observations and more accurate at noise levels below 30%.  相似文献   

Assessing reference evapotranspiration at regional scale based on remote sensing,weather forecast and GIS tools     

《International Journal of Applied Earth Observation and Geoinformation》2017

Reference evapotranspiration (ET_o) is a key component in efficient water management, especially in arid and semi-arid environments. However, accurate ET_o assessment at the regional scale is complicated by the limited number of weather stations and the strict requirements in terms of their location and surrounding physical conditions for the collection of valid weather data. In an attempt to overcome this limitation, new approaches based on the use of remote sensing techniques and weather forecast tools have been proposed.Use of the Land Surface Analysis Satellite Application Facility (LSA SAF) tool and Geographic Information Systems (GIS) have allowed the design and development of innovative approaches for ET_o assessment, which are especially useful for areas lacking available weather data from weather stations. Thus, by identifying the best-performing interpolation approaches (such as the Thin Plate Splines, TPS) and by developing new approaches (such as the use of data from the most similar weather station, TS, or spatially distributed correction factors, CITS), errors as low as 1.1% were achieved for ET_o assessment. Spatial and temporal analyses reveal that the generated errors were smaller during spring and summer as well as in homogenous topographic areas.The proposed approaches not only enabled accurate calculations of seasonal and daily ET_o values, but also contributed to the development of a useful methodology for evaluating the optimum number of weather stations to be integrated into a weather station network and the appropriateness of their locations. In addition to ET_o, other variables included in weather forecast datasets (such as temperature or rainfall) could be evaluated using the same innovative methodology proposed in this study.  相似文献   

拉格朗日插值法在渔业资源评估上的应用     

陈文河  邵青 《广东海洋大学学报》2003,23(6):35-38

应用拉格朗日插值法拟合鱼类体长与体重之间的函数关系 ,使用计算机VB语言进行编写程序 ,与常用的线性回归法、Ricker法进行比较 ,得出体长与体重的关系式为Pn(x) =∑nk=0yklk(x)=∑nk=0(∏nj=0j≠kx-xjxk-xj)yk 。  相似文献   

一种从经纬度网格资料获得正方形网格资料的插值方案     

邓爱军  卢敬华 《成都信息工程学院学报》1990,(Z1)

本文提出了一种把经纬度网格点上的气象要素值转化到正方形网格点上的多项式插值方案。对插值方案作了稳定性讨论和定量及定性分析。结果表明,这种插值方案方便可行,而且有广泛适用性。  相似文献   

天津滨海新区潜在淹没区发展趋势研究   总被引：1，自引：0，他引：1  

张风霜  杨国华  陈聚忠  韩月萍  宋雯  王太松  孙东颖 《震灾防御技术》2008,3(4):459-467

本文利用2006年以前天滓地面沉降监测资料和塘沽、汉沽地区潜在淹没区RTK加密观测资料,以水准监测点为基本研究对象,深入分析研究了每个测点随时间的沉降变化规律,进而“以点带面”绘制了2005年和2011年天津滨海新区地面沉降速率等值线图。同时,还绘制了2005年塘沽、汉沽地区潜在淹没区地面标高等值线分布图,以及预测的2011年塘沽、汉沽地区潜在淹没区的时空分布和面积。最后,提出了应对地面沉降的相关建议,以供政府控制地面沉降时参考。  相似文献   

方向数据插值方法研究     

房亮  刘学军  汤国安 《现代测绘》2006,29(1):3-5,9

方向数据是矢量数据的标量表示,通常标量数据的插值方法不适用于方向数据。本文根据方向数据的特征,把其分解成沿坐标轴的分量,通过对分量数据的插值形成表面,最后合成反算出方向数据,给出了一种对于方向数据的行之有效的插值方法;并用实验进行了验证,对其插值结果和精度进行了统计和分析,取得了较为理想的内插结果。  相似文献