共查询到20条相似文献，搜索用时 15 毫秒
1.
Integrating the Huff Model and Floating Catchment Area Methods to Analyze Spatial Access to Healthcare Services 总被引：3，自引：0，他引：3
Jun Luo 《Transactions in GIS》2014,18(3):436-448
Analysis of spatial access to healthcare services is critical for effective health resource planning. Gravity‐based spatial access models have been widely used to estimate spatial access to healthcare services. Among them, the floating catchment area (FCA) methods have been proved to be informative and helpful to the designation of Health Professional Shortage Areas (HPSAs). This article integrates the Huff Model with the FCA method to articulate population selection on services. Through the proposed approach, population demand on healthcare services is adjusted by a Huff Model‐based selection probability that reflects the impacts of both distance impedance and service site capacity. The new approach moderates the over‐ or under‐estimating of population demand that occurred with previous methods. Furthermore, the method uses a continuous distance impedance weight function instead of the arbitrarily defined subzones of previous studies. A case study of spatial access to primary care in Springfield, MO, showed that the proposed method can effectively moderate the population demand on service sites and therefore can generate more reliable spatial access measures. 相似文献
2.
Emre Ozelkan Gang Chen Burak Berk Ustundag 《International Journal of Digital Earth》2016,9(8):733-747
Spatial interpolation (SI) is currently one of the most common ways to estimate wind speed (Ws). However, classic SI models either ignore the complex geography [e.g. inverse distance weighting (IDW)], or demand high computational resources (e.g. cokriging). This study aimed to develop a simple yet effective SI model for estimating Ws in Eastern Thrace of Turkey. This new method, named MIDW(Ws), is a modified IDW through the integration of IDW with wind profile model, power law (PL), representing the influence of land cover and topography on Ws. Terrain features and elevation data of PL were obtained using normalized difference vegetation index (NDVI) and digital elevation model (DEM), respectively. Results showed superior and comparable performance of MIDW(Ws) to standard IDW and ordinary kriging (OK) across all months of year. Compared to ordinary cokriging (OCK) using DEM as covariate, MIDW(Ws) generated better results in the arid–semiarid seasons (around summer). Local complex atmospheric conditions during rainy seasons (around winter) may have affected the performance of incorporating PL with MIDW(Ws). Generally, the proposed MIDW(Ws) is simpler and easier to implement compared to OCK. For landscape-scale projects, its high computational efficiency and relatively robust performance show potential to deal with large volumes of datasets. 相似文献
3.
以深圳市为研究区，在考虑距离衰减效应的重力型两步移动搜索法（gravity two-step floating catchment area method，G2SFCA）基础上，引入Huff模型，并考虑需求点位置要素及地形要素，分别从供给点竞争、需求点定位、路网距离优化三方面对G2SFCA进行改进，并采用改进的G2SFCA对深圳市室内应急避难场所空间可达性进行研究。实验结果表明，改进的G2SFCA不仅能很好地揭示深圳市各社区室内应急避难场所的空间可达性，而且也能有效反映避难场所可达性与人口密度分布的空间匹配规律，较其他模型更符合现实情况；已建成室内应急避难场所数量、容纳人口及空间可达性的统计与分析结果真实、可靠，相关结论可为深圳市未来的防灾工作以及室内应急避难场所的空间规划与建设提供参考。 相似文献
4.
The Huff model has been widely used in location‐based business analysis to delineate a trade area containing a store’s potential customers. Calibrating the Huff model and its extensions requires empirical location visit data. Many studies rely on labor‐intensive surveys. With the increasing availability of mobile devices, users in location‐based platforms share rich multimedia information about their locations at a fine spatio‐temporal resolution, which offers opportunities for business intelligence. In this research, we present a time‐aware dynamic Huff model (T‐Huff) for location‐based market share analysis and calibrate this model using large‐scale store visit patterns based on mobile phone location data across the 10 most populated US cities. By comparing the hourly visit patterns of two types of stores, we demonstrate that the calibrated T‐Huff model is more accurate than the original Huff model in predicting the market share of different types of business (e.g., supermarkets versus department stores) over time. We also identify the regional variability where people in large metropolitan areas with a well‐developed transit system show less sensitivity to long‐distance visits. In addition, several socioeconomic and demographic factors (e.g., median household income) that potentially affect people’s visit decisions are examined and summarized. 相似文献
5.
Nisha Radhakrishnan R. Aswathy Samson Mathew 《Journal of the Indian Society of Remote Sensing》2017,45(5):815-824
This paper gives an overview of a major application of modern geospatial tools such as remote sensing, GIS and GPS, i.e., 3S technology in estimating travel demand along Indian roads by considering the study area, Tiruchirappalli urban city in Tamil Nadu. In the study, an attempt was made to estimate travel demand based on the current land-use classification as the pattern of travel depends on the type of land use activity in a zone. IRS high resolution image Cartosat-1 of year 2009 was used to extract the land-use information required. The travel demand model developed was validated with the field obtained OD-matrix to understand the accuracy of the method considered. 相似文献
6.
This paper presents a methodology for reformulating the maximal capture problem by using the data representation and manipulation
capabilities of GIS to define: (1) the coverage region captured by each potential facility, and (2) each unique demand region
covered by a specific combination of potential facilities. The formulation is modeled on the maximum covering problem although
the integer restriction on the demand capture variables is relaxed. Because demand regions are not exogenously given, areal
interpolation is used to estimate the demand associated with each of these regions The model is used to determine the location
on a network for a set of home improvement stores that are hypothetically in competition with existing Home Depot stores in
Southeastern New Hampshire.
相似文献
7.
In recent years in India, deregulation has opened the telecommunications market up to new arenas putting pressure on existing organizations to become more efficient. New technologies such as fibre optic cables, efficient terrestrial broadcasting and satellites are offering greatly increased bandwidth. However, the ever-increasing demand to provide low-cost and large area coverage with high reception quality has forced these industries to explore advanced optimization strategies for their network planning. The telecommunications companies have begun to recognize that many of their work practices have spatial elements and data can be used more efficiently. In the present study, a planning strategy for establishing a network of towers for the purpose of mobile communications using remote sensing and raster GIS is demonstrated. In particular, this study addresses how to develop a surface model using IRS-1C PAN stereo pair. This information derived from the satellite data was integrated with raster GIS GRID modelling. The study clearly demonstrates that the IRS data could be utilized for planning a suitable network of towers for telecom applications. 相似文献
8.
将行人的生理因素与GIS路径分析有机结合起来,根据生理学研究进展,建立了步行体能消耗计算模型,并提出了基于坡度转换的等效水平距离计算原则,从而将三维空间距离转换为等体能消耗平面距离,实现了顾及地形起伏的最优路径算法。实验结果表明,该算法具有兼顾坡度与距离关系的优势,提高了路径分析方法的有效性。 相似文献
9.
针对GIS中数据的存储需求及需要解决的问题,结合现有的网络存储技术和存储虚拟化技术,探讨网络存储技术在GIS系统中的应用。 相似文献
10.
Eryong Liu 《制图学和地理信息科学》2016,43(4):321-327
This article presents a new development in measuring the positional error of line features in Geographic Information Systems (GIS), in the form of a new measure for estimating the average error variance of line features, including line segment, polyline, polygon, and curved lines. This average error measure is represented in the form of a covariance matrix derived by an analytical approach. Corresponding error indicators are derived from this matrix. The error of line features mainly results from two factors: (1) an error propagated from the original component points of line features and (2) a model error of interpolation between these points. In this study, a method of average error estimation has been derived regarding the first type error of line features that are interpolated by either linear or cubic interpolation methods. The main contribution of the research is the provision of an error measure to assess the quality of spatial data in application settings. The proposed error models for estimating average error variance of line features in a GIS are illustrated by both simulated and practical experiments. The results show that the line accuracy from a linear interpolation is better than a line interpolated using a cubic model. 相似文献
11.
This article describes GIS-based models successfully developed for predicting the coverage of Cityphone cellular network, visualizing the predicted signal strength, and analyzing the field strength coverage. In order to predict the signal coverage strength of communication network more accurately, the spatial and nonspatial databases of a mobile cellular network are combined by GIS and produce the necessary parameters. A GIS model named COST-231-Walfisch–Ikegami model (WIM) is developed for signal coverage prediction in Ho Chi Minh City. Radio-line-of-sight and nonradio-line-of-sight conditions can be determined by this model. In addition, in case of nonradio-line-of-sight conditions, average building height, building separation, building width, incident radio path, and road orientation with respect to the direct radio path were obtained using GIS. Road orientation loss, multiscreen diffraction loss, and shadowing gain were predicted more accurate by this model. The scale of maps in the experiment was 1:2000 and the average of floor height was 3?m because there were no exact building height measurements. Statistical results show that the path loss predicted by the COST 231 WIM overcame the real path loss of each cell station. And this method can be used for signal coverage prediction of mobile cellular network in urban areas. Compared to the current situation with the Ho Chi Minh City Posts and Telecommunications system, this model can be effectively applied to improve the Cityphone mobile network quality as well as capability. Developed GIS models can help designers in predicting cell station coverage using real spatial maps that make the results more reliable. This research can help network operators improve the network quality and capability with the best investment efficiently. 相似文献
12.
13.
加权总体最小二乘法是理论上估计EIV模型参数相对严密的方法，其迭代过程中涉及的矩阵运算较为耗时，在处理大量级数据时尤其明显。PEIV模型有助于提高加权总体最小二乘法的计算效率。本文基于PEIV模型和经典最小二乘准则给出了一种加权总体最小二乘法算法，算法的推导过程简洁，易于理解，迭代过程中无需重构矩阵，减少了矩阵运算量。最后通过仿真试验验证了算法的可靠性。试验结果表明，本文算法可以取得与现有算法相同的参数估计精度且计算效率更高。 相似文献
14.
One of the simplest location models in terms of its constraint structure in location‐allocation modeling is the location set‐covering problem (LSCP). Although there have been a variety of geographic applications of the set‐covering problem (SCP), the use of the SCP as a facility location model is one of the most common. In the early applications of the LSCP, both potential facility sites as well as demand were represented by points discretely located in geographic space. The advent of geographic information systems (GIS), however, has made possible a greater range of object representations that can reduce representation error. The purpose of this article is to outline a methodology using GIS and K = 3 central place lattices to solve the LSCP when demand is continuously distributed over a bounded area and potential facility sites have not been defined a priori. Although, demand is assumed to exist over an area, it is shown how area coverage can be accomplished by the coverage of a point pattern. Potential facility site distributions based on spacings that are powers of one‐third the coverage distance are also shown to provide more efficient coverage than arbitrarily chosen spacings. Using GIS to make interactive adjustments to an incomplete coverage also provides an efficient alternative to smaller spacings between potential facility sites for reducing the number of facilities necessary for complete coverage. 相似文献
15.
The current paper presents landslide hazard analysis around the Cameron area, Malaysia, using advanced artificial neural networks with the help of Geographic Information System (GIS) and remote sensing techniques. Landslide locations were determined in the study area by interpretation of aerial photographs and from field investigations. Topographical and geological data as well as satellite images were collected, processed, and constructed into a spatial database using GIS and image processing. Ten factors were selected for landslide hazard including: 1) factors related to topography as slope, aspect, and curvature; 2) factors related to geology as lithology and distance from lineament; 3) factors related to drainage as distance from drainage; and 4) factors extracted from TM satellite images as land cover and the vegetation index value. An advanced artificial neural network model has been used to analyze these factors in order to establish the landslide hazard map. The back-propagation training method has been used for the selection of the five different random training sites in order to calculate the factor’s weight and then the landslide hazard indices were computed for each of the five hazard maps. Finally, the landslide hazard maps (five cases) were prepared using GIS tools. Results of the landslides hazard maps have been verified using landslide test locations that were not used during the training phase of the neural network. Our findings of verification results show an accuracy of 69%, 75%, 70%, 83% and 86% for training sites 1, 2, 3, 4 and 5 respectively. GIS data was used to efficiently analyze the large volume of data, and the artificial neural network proved to be an effective tool for landslide hazard analysis. The verification results showed sufficient agreement between the presumptive hazard map and the existing data on landslide areas. 相似文献
16.
Approaches for delineating landslide hazard areas using different training sites in an advanced artificial neural network model 总被引：10，自引：0，他引：10
The current paper presents landslide hazard analysis around the Cameron area, Malaysia, using advanced artificial neural networks
with the help of Geographic Information System (GIS) and remote sensing techniques. Landslide locations were determined in
the study area by interpretation of aerial photographs and from field investigations. Topographical and geological data as
well as satellite images were collected, processed, and constructed into a spatial database using GIS and image processing.
Ten factors were selected for landslide hazard including: 1) factors related to topography as slope, aspect, and curvature;
2) factors related to geology as lithology and distance from lineament; 3) factors related to drainage as distance from drainage;
and 4) factors extracted from TM satellite images as land cover and the vegetation index value. An advanced artificial neural
network model has been used to analyze these factors in order to establish the landslide hazard map. The back-propagation
training method has been used for the selection of the five different random training sites in order to calculate the factor’s
weight and then the landslide hazard indices were computed for each of the five hazard maps. Finally, the landslide hazard
maps (five cases) were prepared using GIS tools. Results of the landslides hazard maps have been verified using landslide
test locations that were not used during the training phase of the neural network. Our findings of verification results show
an accuracy of 69%, 75%, 70%, 83% and 86% for training sites 1, 2, 3, 4 and 5 respectively. GIS data was used to efficiently
analyze the large volume of data, and the artificial neural network proved to be an effective tool for landslide hazard analysis.
The verification results showed sufficient agreement between the presumptive hazard map and the existing data on landslide
areas. 相似文献
17.
孙晓华 《测绘与空间地理信息》2014,(8):125-127
随着私家车数量的快速增长,居民住宅区域停车压力已经越来越大,停车刚性需求与居住区公共空间"相争"的矛盾将会长期存在。如何科学、有效地解决私家车快速增长所带来的停车需求问题已经成为不得不面对的严峻现实。本文利用网络上现有的图像数据,选取福州市龙苑C区为试验区,通过GIS空间分析技术提取居民住宅区域内停车区域的分布信息。以停车区域面积、单位泊车面积为自变量,以停车容量为因变量,通过面积比例法得出停车容量与停车区域面积、单位泊车面积的关系,并由此建立停车容量估算模型,最后利用该估算模型实现基于GIS的居民住宅区域停车容量估算,并利用实测数据对估算模型进行了验证。 相似文献
18.
针对城市雨水网络传统规划手段落后导致城市地面雨水不能及时有效地收集和排除的问题,该文提出了基于GIS和暴雨洪水管理模型(SWMM)集成的带权雨水网络的构建方法。通过软件互操作模式将SWMM模型封装成.NET托管动态库,实现了其与GIS空间分析组件的无缝集成;以新城区竖向设计高程和规划路网为基础数据,构建顾及路网的格网DEM;基于新城区规划用地类型和研究区暴雨模型,运用GIS空间分析实现了水文参数的自动提取;进一步率定雨水管网权重因子,利用GIS几何网络分析实现了带权有向雨水网络自动构建及布局优化。实验结果表明:该方法较传统方法工作效率更高,且布网方案、雨水出口选择、管力计算等方面更加科学合理。 相似文献
19.
This paper compares the differences between the mathematical model in graph theory and GIS network analysis model. Thus it claims that the GIS network analysis model needs to solve. Then this paper introduces the spatial data management methods in object-relation database for GIS and discusses its effects on the network analysis model. Finally it puts forward the GIS network analysis model based on the object-relation database. The structure of the model is introduced in detail and research is done to the internal and external memory data structure of the model. The results show that it performs well in practice. 相似文献
20.
YUEPeng WANGYandong GONGJianya HUANGXianfeng 《地球空间信息科学学报》2004,7(3):174-179
This paper compares the differences between the mathematical model in graph theory and GIS network analysis model. Thus it claims that the GIS network analysis model needs to solve. Then this paper introduces the spatial data management methods in object-relation database for GIS and discusses its effects on the network analysis model. Finally it puts forward the GIS network analysis model based on the object-rela-tion database. The structure of the model is introduced in detail and research is done to the internal and external memory data structure of the model. The results show that it performs well in practice. 相似文献