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1.
Qiang Cai Gerard Rushton Budhendra Bhaduri Edward Bright Phillip Coleman 《Transactions in GIS》2006,10(4):577-598
The objective of this research is to compute population estimates by age and sex for small areas whose boundaries are different from those for which the population counts were made. In our approach, population surfaces and age‐sex proportion surfaces are separately estimated. Age‐sex population estimates for small areas and their confidence intervals are then computed using a binomial model with the two surfaces as inputs. The approach was implemented for Iowa using a 90 m resolution population grid (LandScan USA) and U.S. Census 2000 population. Three spatial interpolation methods, the areal weighting (AW) method, the ordinary kriging (OK) method, and a modification of the pycnophylactic method, were used on Census Tract populations to estimate the age‐sex proportion surfaces. To verify the model, age‐sex population estimates were computed for paired Block Groups that straddled Census Tracts and therefore were spatially misaligned with them. The pycnophylactic method and the OK method were more accurate than the AW method. The approach is general and can be used to estimate subgroup‐count types of variables from information in existing administrative areas for custom‐defined areas used as the spatial basis of support in other applications. 相似文献
2.
As an important GIS function, spatial interpolation is one of the most often used geographic techniques for spatial query, spatial data visualization, and spatial decision-making processes in GIS and environmental science. However, less attention has been paid on the comparisons of available spatial interpolation methods, although a number of GIS models including inverse distance weighting, spline, radial basis functions, and the typical geostatistical models (i.e. ordinary kriging, universal kriging, and cokriging) are already incorporated in GIS software packages. In this research, the conceptual and methodological aspects of regression kriging and GIS built-in interpolation models and their interpolation performance are compared and evaluated. Regression kriging is the combination of multivariate regression and kriging. It takes into consideration the spatial autocorrelation of the variable of interest, the correlation between the variable of interest and auxiliary variables (e.g., remotely sensed images are often relatively easy to obtain as auxiliary variables), and the unbiased spatial estimation with minimized variance. To assess the efficiency of regression kriging and the difference between stochastic and deterministic interpolation methods, three case studies with strong, medium, and weak correlation between the response and auxiliary variables are compared to assess interpolation performances. Results indicate that regression kriging has the potential to significantly improve spatial prediction accuracy even when using a weakly correlated auxiliary variable. 相似文献
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一种基于主成分分析的协同克里金插值方法 总被引：1，自引：0，他引：1
针对协同克里金插值方法在插值时,辅助变量较多造成计算复杂度增加,而辅助变量较少引起插值精度降低这一问题,提出了一种基于主成分分析的协同克里金插值方法（PCA-CoKriging）。该方法首先使用主成分分析对插值相关变量进行将维,得到较少几个综合指标,然后里利用这几个综合指标作为辅助变量进行协同克里金插值。为验证该方法的有效性和数据分布对该方法的影响,本文选取了2016年北京市范围内4个季节中PM2.5浓度满足正态分布效果不同的4组数据,分别使用PCA-CoKriging和普通克里金插值方法、常规协同克里金插值方法,进行了插值试验。结果表明,本文方法与普通克里金插值方法、常规协同克里金插值法在4组试验中的平均绝对误差分别为4.91、6.04、5.61,平均均方根误差分别为6.65、8.76、7.57。综合比较,本文方法比常规协同克里金插值的平均绝对误差与均方根误差分别提升了10.73%、12.56%,比普通克里金插值法的平均绝对误差与均方根误差分别提升了18.71%、24.09%。 相似文献
5.
Population at risk of crime varies due to the characteristics of a population as well as the crime generator and attractor places where crime is located. This establishes different crime opportunities for different crimes. However, there are very few efforts of modeling structures that derive spatiotemporal population models to allow accurate assessment of population exposure to crime. This study develops population models to depict the spatial distribution of people who have a heightened crime risk for burglaries and robberies. The data used in the study include: Census data as source data for the existing population, Twitter geo-located data, and locations of schools as ancillary data to redistribute the source data more accurately in the space, and finally gridded population and crime data to evaluate the derived population models. To create the models, a density-weighted areal interpolation technique was used that disaggregates the source data in smaller spatial units considering the spatial distribution of the ancillary data. The models were evaluated with validation data that assess the interpolation error and spatial statistics that examine their relationship with the crime types. Our approach derived population models of a finer resolution that can assist in more precise spatial crime analyses and also provide accurate information about crime rates to the public. 相似文献
6.
《制图学和地理信息科学》2013,40(4):273-274
A number of areal interpolation methods have been developed to estimate population for overlapping, discontinuous, or fragmented areas. Previous studies examined the relative accuracy of various methods; this research advances those endeavors by comparing the effectiveness of seven different methods using a national random sample of census block groups and blocks. As the results show, the areal interpolation methods produce good population estimates for nested census blocks except in areas of heterogeneous land use or unusual contexts. In addition, estimation conducted in areas with small populations or low population density was vulnerable to high percentage error. Amongst the different methods, road network allocation and statistical regression (with area and roads as predictors) produced the best population estimates for the sample blocks. 相似文献
7.
人口统计数据的空间分布化研究 总被引：21，自引：0，他引：21
分析了传统的人口空间分布密度衰减函数－指数型和Gauss型，指出了其应用的局限性，对于有两个中心以上的城市，提出了将人口统计数据空间分布化的思路和方法。 相似文献
8.
This research evaluates the performance of areal interpolation coupled with dasymetric refinement to estimate different demographic attributes, namely population sub-groups based on race, age structure and urban residence, within consistent census tract boundaries from 1990 to 2010 in Massachusetts. The creation of such consistent estimates facilitates the study of the nuanced micro-scale evolution of different aspects of population, which is impossible using temporally incompatible small-area census geographies from different points in time. Various unexplored ancillary variables, including the Global Human Settlement Layer (GHSL), the National Land-Cover Database (NLCD), parcels, building footprints and the proprietary ZTRAX® dataset are utilized for dasymetric refinement prior to areal interpolation to examine their effectiveness in improving the accuracy of multi-temporal population estimates. Different areal interpolation methods including Areal Weighting (AW), Target Density Weighting (TDW), Expectation Maximization (EM) and its data-extended approach are coupled with different dasymetric refinement scenarios based on these ancillary variables. The resulting consistent small area estimates of white and black subpopulations, people of age 18–65 and urban population show that dasymetrically refined areal interpolation is particularly effective when the analysis spans a longer time period (1990–2010 instead of 2000–2010) and the enumerated population is sufficiently large (e.g., counts of white vs. black). The results also demonstrate that current census-defined urban areas overestimate the spatial distribution of urban population and dasymetrically refined areal interpolation improves estimates of urban population. Refined TDW using building footprints or the ZTRAX® dataset outperforms all other methods. The implementation of areal interpolation enriched by dasymetric refinement represents a promising strategy to create more reliable multi-temporal and consistent estimates of different population subgroups and thus demographic compositions. This methodological foundation has the potential to advance micro-scale modeling of various subpopulations, particularly urban population to inform studies of urbanization and population change over time as well as future population projections. 相似文献
9.
Spatial interpolation has been widely used to improve the spatial granularity of data, or to mediate between inconsistent zoning schemes of spatial data. Traditional areal interpolation methods translate values of source zones to those of target zones. These methods have difficulty in dealing with flow data, as each instance is associated with a pair of zones. This study develops a new concept, flow line interpolation, to fill the abovementioned gap. We also develop a first flow line interpolation method to estimate commuting flow data between spatial units in a target zoning scheme based on such data in a source zoning scheme. Three models (i.e., areal‐weighted, intelligent, and gravity‐type flow line interpolation) are presented. To test the estimation accuracy and the application potential of these models, a case study of Fulton County in Georgia is conducted. The results reveal that both the areal‐weighted and intelligent models are very promising flow line interpolation methods. 相似文献
10.
《制图学和地理信息科学》2013,40(2):103-121
This paper describes techniques to compute and map dasymetric population densities and to areally interpolate census data using dasymetrically derived population weights. These techniques are demonstrated with 1980-2000 census data from the 13-county Atlanta metropolitan area. Land-use/land-cover data derived from remotely sensed satellite imagery were used to determine the areal extent of populated areas, which in turn served as the denominator for dasymetric population density computations at the census tract level. The dasymetric method accounts for the spatial distribution of population within administrative areas, yielding more precise population density estimates than the choroplethic method, while graphically representing the geographic distribution of populations. In order to areally interpolate census data from one set of census tract boundaries to another, the percentages of populated areas affected by boundary changes in each affected tract were used as adjustment weights for census data at the census tract level, where census tract boundary shifts made temporal data comparisons difficult. This method of areal interpolation made it possible to represent three years of census data (1980, 1990, and 2000) in one set of common census tracts (1990). Accuracy assessment of the dasymetrically derived adjustment weights indicated a satisfactory level of accuracy. Dasymetrically derived areal interpolation weights can be applied to any type of geographic boundary re-aggregation, such as from census tracts to zip code tabulation areas, from census tracts to local school districts, from zip code areas to telephone exchange prefix areas, and for electoral redistricting. 相似文献
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对于十分规则的道路网(城市道路)来说构造网眼是十分容易的,且得到的道路网眼完整性较高,然而对于乡村道路,由于数据采集习惯或数据质量的影响,道路在居民地附近容易断开,导致计算机不能构造完整的网眼。本文针对这个问题,提出了利用居民地聚类和缓冲区分析的方法辅助道路网眼的构建,从而提高了乡镇郊区道路网眼的完整性,为采用网眼合并的方式进行综合的方法,以及各种基于网眼的空间分析提供了有效支撑。 相似文献
12.
Yukio Sadahiro 《Journal of Geographical Systems》1999,1(4):323-346
This paper discusses the accuracy of spatial data estimated by areal interpolation, a process of transferring data from one
zonal system to another. A stochastic model is proposed which represents areal interpolations in diverse geographic situations.
The model is used to examine the relationship between estimation accuracy and the spatial distribution of estimation error
from a theoretical viewpoint. The analysis shows that the uniformity in error distribution improves the accuracy of areal
interpolation. Four areal interpolation methods are then assessed through numerical examinations. From this it is found that
the accuracy of simple interpolation methods heavily depends on the appropriateness of their hypothetical distributions, whereas
the accuracy of intelligent methods depends on the fitness of the range of supplementary data for that of true distribution.
Received: 19 February 1999/Accepted 17 September 1999 相似文献
13.
《制图学和地理信息科学》2013,40(2):77-102
This paper discusses the importance of determining an accurate depiction of total population and specific sub-population distribution for urban areas in order to develop an improved "denominator," which would enable the calculation of more correct rates in GIS analyses involving public health, crime, and urban environmental planning. Rather than using data aggregated by arbitrary administrative boundaries such as census tracts, we use dasymetric mapping, an areal interpolation method using ancillary information to delineate areas of homogeneous values. We review previous dasymetric mapping techniques (which often use remotely sensed land-cover data) and contrast them with our technique, Cadastral-based Expert Dasymetric System (CEDS), which is particularly suitable for urban areas. The CEDS method uses specific cadastral data, land-use filters, modeling by expert system routines, and validation against various census enumeration units and other data. The CEDS dasymetric mapping technique is presented through a case study of asthma hospitalizations in the Bronx, New York City, in relation to proximity buffers constructed around major sources of air pollution. The case study shows the impact that a more accurate estimation of population distribution has on a current environmental justice and health disparities research project, and the potential of CEDS for other GIS applications. 相似文献
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Classical multivariate analyses are based on matrix algebra and enable the analysis of a table containing measurements of a set of variables for a set of sites. Incomplete mapped data consist of measurements of a set of variables recorded for the same geographical region but for different zonal systems and with only a partial sampling of this zone. This kind of data cannot be analysed with usual multivariate methods because there is no common system of sites for all variables. We propose a new approach using GIS technology and NIPALS, an iterative multivariate method, to analyse the spatial patterns of this kind of data. Moreover, an extension of our method is that it can be used for areal interpolation purposes. We illustrate the method in analysing data concerning the distribution of roe deer weights over several years in a reserve. 相似文献
15.
Paul A Zandbergen 《Transactions in GIS》2011,15(Z1):5-27
Mismatching sets of boundaries present a persistent problem in spatial analysis for many different applications. Dasymetric mapping techniques can be employed to estimate population characteristics of small areas that do not correspond to census enumeration boundaries. Several types of ancillary data have been used in dasymetric mapping but performance is often limited by their relatively coarse resolution and moderate correspondence to actual population counts. The current research examines the performance of using high resolution ancillary data in the form of individual address point datasets which represent the locations of all addressable units within a jurisdiction. The performance of address points was compared with several other techniques, including areal weighting, land cover, imperviousness, road density and nighttime lights. Datasets from 16 counties in Ohio were used in the analysis, reflecting a range of different population densities. For each technique the ancillary data sources were employed to estimate census block group population counts using census tracts as source zones, and the results were compared with the known block group population counts. Results indicate that address points perform significantly better compared with other types of ancillary data. The overall error for all block groups (n = 683) using address points is 4.9% compared with 10.8% for imperviousness, 11.6% for land cover, 13.3% for road density, 18.6% for nighttime lights and 21.2% for areal weighting. Using only residential address points rather than all types of locations further reduces this error to 4.2%. Analysis of the spatial patterns in the relative performance of the various techniques revealed that address points perform particularly well in low density rural areas, which typically present challenges for traditional dasymetric mapping techniques using land cover datasets. These results provide very strong support for the use of address points for small area population estimates. Current developments in the growing availability of address point datasets and the implications for spatial demographic analyses are discussed. 相似文献
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空间数据表示方法和空间数据插值方法是3D-GIS研究的基本问题。3维空间数据的曲面重建有着广泛的应用前景,也是当前国际上的研究热点之一。Crust算法是一种基于计算几何中的Voronoi周期图的曲面重建算法,它算法简单,重建结果精细,但是由于计算量太大,其应用受到了限制,文中采用基于VTK(Visualization Tool Kit)表现3D空间数据的表示方法,提出了一个新的三角网格内插的曲面重建算法,并给出了实例以说明该方法的有效性。 相似文献
18.
网络空间同位模式的加色混合可视化挖掘方法 总被引：1，自引：0，他引：1
同位模式挖掘是空间数据挖掘的热点问题之一,应用领域广泛。已有的同位模式挖掘方法一般采用统计或数据挖掘的方式,要求对复杂的数学公式、算法及相关参数等有深刻的理解,主要针对同质的欧式空间中地理现象。而城市空间中人为地理现象大多发生在网络空间,鉴于此,本文提出了一种网络空间同位模式可视化挖掘方法。该方法利用视觉语言表达网络空间现象之间的影响和交互作用。首先,利用网络空间核密度估计表达网络空间现象的分布情况和影响范围,为网络空间现象的同位模式挖掘提供支持,并建立单个地理现象分布情况与颜色之间的映射;然后基于色光加色混合原理获得两个地理现象相互影响的认知,借以挖掘空间同位模式。本文提出的方法属于形象思维,具有直观,形象和易感受等特点。 相似文献
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Traditionally, areal interpolation has referred to techniques for transferring attribute values from one partitioning of space to a different partition of space but this is only one of several situations that create the need for estimating unknown data values for areal units. This paper presents a categorization of four areal interpolation problems that includes the "missing" data problem, the traditional "alternative geography" problem, the overlay of a choropelth and an area-class data layer, and the overlay of two choropleth data layers and demonstrates the relationship between the last three problems and general spatial interaction modelling. The "alternative geography" and overlay of choropleth and area-class data layers mirrors a singly constrained spatial interaction model while the overlay of two choropleth layers is analogous to a doubly constrained interaction model. Iterative proportional fitting techniques with and without ancillary data are developed to solve these three classes of problems. 相似文献
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针对地图上河流的自动综合,建立了基于河段的河系结构化数据模型,该模型充分考虑了河段与河段、河段与面状水系要素之间的空间关系,以及河系河段的层次关系;建立了一种面向自动综合的河系结构化数据模型,模型包含了大量水系综合所需要的信息。基于上述数据模型,设计了一种方便快捷的河系结构化算法,该算法较好地克服了现有河系结构化算法只针对河流以及只适用于形态相对简单的河系的缺陷,较为全面地考虑了河系结构中出现的各种复杂问题,具有较强的实用性。 相似文献