基于空间可视化的气温插值方法比较     

焦永清  李斌  张坤 《测绘工程》2013,(5):62-64

基于GIS的可视化、空间插值和叠加分析功能,以1982年全国684个气温台站观测数据为插值实验样本,探讨可视条件下空间插值几种主要方法的优劣及适用性,通过对年均气温预测精度的对比及陕西省年均气温预测图的分析,得出就效果而言普通克里格空间插值最优、反距离加权法次之而规则样条法相对较差的初步结果。  相似文献   

DEM内插算法与精度评定研究     

王晞 《江苏测绘》2013,(5):21-23,29

本文分析了DEM数据产品的误差源、内插算法的误差模型,简要介绍了目前DEM数据产品精度评定的指标与方法途径.通过介绍DEM引出了数字高程模型内插方法,比较了各种DEM内插方法,并且分析了模型精度.  相似文献   

基于多项式拟合的移去恢复法求解对流层天顶延迟的研究     

赵静  尹慧芳  党亚民  薛树强  杨强 《测绘科学》2013,38(4)

本文针对基于区域GPS网内插流动站对流层天顶延迟(ZTD)时存在的问题,提出了基于多项式拟合的移去恢复法.该方法利用对流层天顶延迟与高程之间的强相关性,通过多项式拟合将对流层天顶延迟中与高程相关的信息移去后再进行内插求解.采用SCIGN的GPS数据进行实验,结果表明:基于多项式拟合的移去恢复法的插值精度明显高于传统的反距离加权直接内插法,特别对于高程明显偏离参考站总体高程的流动站具有较好的改进效果.  相似文献   

不同插值方法对CORS高程时间序列的影响分析   总被引：2，自引：0，他引：2  

田慧  程鹏飞  秘金钟 《测绘科学》2013,38(1):16-17,46

在CORS站高程时间序列的研究中,当连续缺失较多数据时,插值显得尤为重要。为了较好地解决这个问题,本文尝试采用正交多项式拟合的方法,分别利用正交多项式拟合、拉格朗日和三次样条等插值方法对高程时间序列进行插值,并对不同方法的插值结果进行了分析比较,验证了正交多项式拟合的可行性及有效性。结果表明:在高程时间序列插值中,三次样条插值结果较差;连续缺失3个点及以下时,正交多项式拟合、拉格朗日插值结果均较好,插值效果相当;随着缺失点数量的增加,正交多项式拟合结果要优于另2种方法。  相似文献   

Finding appropriate interpolation techniques for topographic surface generation for mudslide risk zonation     

Anujit Vansarochana  Nitin K. Tripathi  Roberto Clemente 《国际地球制图》2013,28(4):313-332

Mudslides and debris flows are now more common problems in tropical regions than landslides. This article addresses the issue of modelling mudslide-susceptible locations using an information value approach. Landsat 7 (ETM+) was employed to create a land-use map with limited field checks. Other parameters considered were lineament, road, soil, stream network and lithology. Topographic parameters such as slope and aspect play a dominant role in slope stability studies. Maps for slope and aspects were developed from a digital elevation model using statistical surface interpolation techniques. This article offers insight into the importance of the selection of suitable surface interpolation techniques. The three surface interpolation techniques evaluated in the study were: inverse distance weighted, Kriging and Spline. These were found to have varied accuracies of interpolation surfaces for all parameters, including elevation, slope and aspect. Surfaces offering the best accuracy were adopted for the information value approach for mudslide susceptibility zonation.  相似文献   

A space–time parallel framework for fine-scale visualization of pollen levels across the Eastern United States     

Michael R. Desjardins  Alexander Hohl  Adam Griffith 《制图学和地理信息科学》2013,40(5):428-440

ABSTRACT

Allergic rhinitis (hay fever) resulting from seasonal pollen affects 15–30% of the population in the United States, and can exacerbate several related conditions, including asthma, atopic eczema, and allergic conjunctivitis. Timely monitoring, accurate prediction, and visualization of pollen levels are critical for public health prevention purposes, such as limiting outdoor exposure or physical activity. The low density of pollen detecting stations and complex movement of pollen represent a challenge for accurate prediction and modeling. In this paper, we reconstruct the dynamics of pollen variation across the Eastern United States for 2016 using space–time interpolation. Pollen levels were extracted according to a stratified spatial sampling design, augmented by additional samples in densely populated areas. These measurements were then used to estimate the space–time cross-correlation, inferring optimal spatial and temporal ranges to calibrate the space–time interpolation. Given the computational requirements of the interpolation algorithm, we implement a spatiotemporal domain decomposition algorithm, and use parallel computing to reduce the computational burden. We visualize our results in a 3D environment to identify the seasonal dynamics of pollen levels. Our approach is also portable to analyze other large space–time explicit datasets, such as air pollution, ash clouds, and precipitation.  相似文献   

Analysis of radial basis function interpolation approach     

You-Long Zou  Fa-Long Hu  Can-Can Zhou  Chao-Liu Li  Keh-Jim Dunn 《应用地球物理》2013,10(4):397-410

The radial basis function （RBF） interpolation approach proposed by Freedman is used to solve inverse problems encountered in well-logging and other petrophysical issues. The approach is to predict petrophysical properties in the laboratory on the basis of physical rock datasets, which include the formation factor, viscosity, permeability, and molecular composition. However, this approach does not consider the effect of spatial distribution of the calibration data on the interpolation result. This study proposes a new RBF interpolation approach based on the Freedman＇s RBF interpolation approach, by which the unit basis functions are uniformly populated in the space domain. The inverse results of the two approaches are comparatively analyzed by using our datasets. We determine that although the interpolation effects of the two approaches are equivalent, the new approach is more flexible and beneficial for reducing the number of basis functions when the database is large, resulting in simplification of the interpolation function expression. However, the predicted results of the central data are not sufficiently satisfied when the data clusters are far apart.  相似文献   

Interpolating U.S. Decennial Census Tract Data from as Early as 1970 to 2010: A Longitudinal Tract Database     

John R. Logan  Zengwang Xu  Brian J. Stults 《The Professional geographer》2013,65(3):412-420

Differences in the reporting units of data from diverse sources and changes in units over time are common obstacles to analysis of areal data. We compare common approaches to this problem in the context of changes over time in the boundaries of U.S. census tracts. In every decennial census, many tracts are split, consolidated, or changed in other ways from the previous boundaries to reflect population growth or decline. We examine two interpolation methods to create a bridge between years, one that relies only on areal weighting and another that also introduces population weights. Results demonstrate that these approaches produce substantially different estimates for variables that involve population counts, but they have a high degree of convergence for variables defined as rates or averages. Finally, the article describes the Longitudinal Tract Database (LTDB), through which we are making available public-use tools to implement these methods to create estimates within 2010 tract boundaries for any tract-level data (from the census or other sources) that are available for prior years as early as 1970.  相似文献   

Jobs and the Single Parent: An Analysis of Accessibility to Employment in Toronto     

Antonio Páez  Steven Farber  Ruben Mercado  Matthew Roorda  Catherine Morency 《Urban geography》2013,34(6):815-842

Abstract

In this article, we undertake an analysis of accessibility to jobs from the perspective of single-parent household members. Individuals in this demographic segment are of interest due to the fact they often face the double burden of household and employment responsibilities. A case study of the city of Toronto in Canada, an urban area that has seen an increase in absolute and relative numbers of single-parent households in recent years, is presented. Analysis is based on the application of relative accessibility deprivation indicators (RADI), which are calculated using model-based estimates of distance traveled for various population segments, as well as employment data for the city and its surroundings. The results of the analysis indicate that there are substantial differences in the levels of accessibility to jobs between members of single-parent households, in particular females, and members of other types of households.  相似文献   

Cartographic generalisation of lines based on a B‐spline snake model     

E. Guilbert  E. Saux 《International journal of geographical information science》2013,27(8):847-870

The automation of cartographic map production is still an important research field in Geographical Information Systems (GIS). With the increasing development of monitoring and decision‐aid systems either on computer networks or wireless networks, efficient methods are needed to visualise geographical data while respecting some application constraints (accuracy, legibility, security, etc.). This paper introduces a B‐spline snake model to deal with the current operators involved in the cartographic generalisation process of lines. This model enables us to perform those operators with a continuous approach. In order to avoid local conflicts such as intersections or self‐intersections, the consistency of the lines is checked and discrete operations such as segment removal are performed during the process. We apply the method to map production in the highly constrained domain of maritime navigation systems. Experimental results of marine chart generalisation yield some discussions about generalisation robustness and quality.  相似文献