A Note on Trip Benefits in Spatial Interaction Models

We extend the well-known transport users' benefits measure (TUB) for the doubly-constrained spatial interaction model derived by Williams (1976). The original formula expresses the TUB as composed by two terms associated with the origin and the destination zones. First, the TUB is associated here with trips instead of zones, providing a natural interpretation as a rule-of-a-half measure of benefit under inelastic demand (for the short-run case). Second, a TUB formula for the long-run case is derived, that is, when the total number of trips, trip origins, and trip destinations change. We then propose updated measures of accessibility for location behavior.     

国外旅游线路空间模式研究进展

旅游线路空间模式实质上是游客在目的地区域对停留空间和消费空间的理性选择与线性组合,是具有典型空间属性的社会文化地理现象和经济地理现象,涉及了作为旅游景点和旅游目的地的点状地理要素和作为旅游线路的线状地理要素以及旅游目的地体系构成的区域等面状地理要素。从文献综述的角度对不同尺度旅游线路模式的空间模型、目的地类型、游客旅行行为特征、模式选择影响因素以及理论基础进行了总结,在此基础上结合国内研究对旅游线路模式今后的研究方向提出了建议。     

On Covering Problems and the Central Facilities Location Problem

A number of variations of facilities location problems have appeared in the research literature in the past decade. Among these are problems involving the location of multiple new facilities in a discrete solution space, with the new facilities located relative to a set of existing facilities having known locations. In this paper a number of discrete solution space location problems are treated. Specifically, the covering problem and the central facilities location problem are shown to be related. The covering problem involves the location of the minimum number of new facilities among a finite number of sites such that all existing facilities (customers) are covered by at least one new facility. The central facilities location problem consists of the location of a given number of new facilities among a finite number of sites such that the sum of the weighted distances between existing facilities and new facilities is minimized. Computational experience in using the same heuristic solution procedure to solve both problems is provided and compared with other existing solution procedures.     

A Cost-Benefit Location-Allocation Model for Public Facilities: An Econometric Approach

This research develops and operationalizes a facility location-allocation model based on cost-benefit principles derived from welfare economics. Despite the theoretical advantages of cost-benefit location-allocation models, the difficulties associated with estimating household preferences for public facilities have heretofore prevented their application. This research demonstrates that the hedonic-pricing methodology can be effectively used to estimate preferences for public facilities. Specifically, household preferences for Baltimore public middle schools were estimated from the spatial variation in housing prices using the random bidding model. To provide an example of the methodology, the cost-benefit location-allocation objective function was maximized to simultaneously determine the optimal number, quality, and locations of Baltimore middle schools. The cost-benefit approach to facility location constitutes a major improvement over existing methods because it directly incorporates user preferences into the objective function and because the number and quality of facilities can be determined endogenously rather than being specified as a constraint a priori.     

A Generalization of the Utility Theory Approach To the Problem of Spatial Interaction

The derivation of the gravity model from utility theory is reformulated and generalized in order to show (1) how both the number of trips to individual destinations and the total travel budget may be determined simultaneously, and (2) how the effect of both distance and destination quality on trip distribution and total budget may be analyzed. Results are compared with the revealed space preference approach and are found to be superior in dealing theoretically with trip frequency and the effects of spatial context. For empirical applications, however, the revealed preference approach is advantageous.     

The Zone Definition Problem in Location-Allocation Modeling

Location-allocation modeling is a frequently used set of techniques for solving a variety of locational problems, some of which can be politically sensitive. The typical application of a location-allocation model involves locating facilities by selecting a set of sites from a larger set of candidate sites, with the selection procedure being a function of “optimality” in terms of the allocation of demand to the selected sites. In this paper we examine the sensitivity of one particular type of location-allocation model, the p-median procedure, to the definition of spatial units for which demand is measured. We show that a p-median solution is optimal only for a particular definition of spatial units and that variations in the definition of spatial units can cause large deviations in optimal facility locations. The broad implication of these findings is that the outcome of any location-allocation procedure using aggregate data should not be relied upon for planning purposes. This has important implications for a large variety of applications.     

A TRANSLOG APPROACH TO CONSUMER SPATIAL BEHAVIOR*

With the view that travel behavior stems from the principle of utility maximization, in this paper I present a spatial translog demand model that accounts for interdependence among travel alternatives and that handles varying elasticities of substitution for various destination pairs. Using simulation as the mode of inquiry, this model describes the effect of spatial size, spatial configuration, and spatial substitution on spatial interaction. In addition to indicating how varying spatial sizes and configurations affect the average trip length and the trip making pattern, the simulation results also point out the possible effect of having spatially dependent locations in the system. Competing destinations increase the attractiveness of nearby locations, and complementary destinations reduce the impeding effect of space. The model is primarily relevant to the demand for shopping trips.     

The Aggregation Problem in Location-Allocation

Location-allocation solutions based on aggregate estimates of demand are subject to error because of a loss of locational information during aggregation. It is shown that any method to remove or reduce uncertainty must be solution-specific and therefore impractical, for both median and center classes of problems. The significance of the error is illustrated by simulation of solutions to a number of artificial and real problems. It is suggested that aggregation problems be specifically addressed in applications of location-allocation models, and possible methods are proposed.     

上海市民近程出游力与目的地选择评价研究

本文通过近3年的调查研究,运用旅游地理学分析方法,对影响上海市民周末旅游、一日游和休闲出行等的近程出游活动的社会经济因素进行了分析,然后对市民的目的地选择行为和感应评价作了研究。这一研究的方法和结论,无论对城市旅游、休闲产业的发展,还是对旅游地理学理论的进步,都有一定裨益。     

THE OPTIMAL LOCATIONS OF MULTIPLE BRIDGES,CONNECTING FACILITIES,OR PRODUCT VARIETIES*

ABSTRACT This paper considers the optimal locations of two or more facilities, and the optimal number of facilities, when trips are made in pairs. The results are the same as standard models of spatial competition when there is perfect matching, but not when there is random matching. The first interpretation is bridges across a river, with residential locations on one side matched perfectly or randomly to jobs on the other side. The second interpretation is connecting facilities, such as tennis courts or restaurants where pairs of consumers meet. The third interpretation is product differentiation, with husbands and wives jointly choosing from among varieties.     

"时空缩减"背景下客源市场空间分布及演变趋势分析

距离因素是影响旅游地客源空间分布与演化的关键因素,现代交通技术的变革,信息化及网络技术的普及造成的时空汇聚使距离因素弱化。以距离因素的多维尺度特征为切入点,分析了“时空缩减”背景下的游客出游距离的变化趋势;构建旅游地客源市场演化的理论模型,用逆向思维的方法,探讨了旅游地吸引半径的变化动向;结合游客出游距离和旅游地吸引半径的演化趋势,阐述了旅游地客源市场的时空动态演化过程并剖析了其内在机理;最后通过实证研究对理论模型进行扩展和检验,为旅游地客源拓展提供了理论依据及实践参考。     

基于购物出行的沈阳市居住与商业空间匹配关系研究

居住与商业空间是影响城市空间布局的重要因素.本研究利用空间分析法、高斯两步移动搜索法和不一致指数测度沈阳市居住与商业空间的分布、居民购物活动的可达性以及居住与商业空间的匹配关系.研究表明:①沈阳市居住设施具有中部强外围弱的空间集聚特征,南部外围居住设施数量较少、集聚程度较弱.②中部太原街、皇城、北站、兴工等都市商贸中心...     

Disaggregate Migration Behavior and the Volume of Interregional Migration

Nested multinomial logit models are used to investigate migration behavior during the 1971–74 period for a large sample of the population of Ecuador. The nested form of the model makes it possible to test hypotheses about the importance of destination characteristics in conditioning the odds for out-migration. Our empirical results indicate that the odds for migration from each origin are conditioned by the expected utilities of the available set of destinations, as well as characteristics of the origins and the personal characteristics of potential migrants. The association between destination characteristics and the frequency of out-migration allows the total volumes of migration to be adjusted to interregional differences in place-specific utilities.     

AN ALGORITHM FOR THE SPATIAL PRICE EQUILIBRIUM PROBLEM ON A GENERAL NETWORK IN THE SPACE OF THE PATH FLOWS*

ABSTRACT. The spatial price equilibrium on a general network may be formulated as a nonlinear-cost mathematical programming problem with simple constraints, when the decision variables are the path flows. The solution of this problem is difficult due to the very large number of variables (paths) and the impracticality of generating all the paths from all the origins to all the destinations. In this paper, we develop a Gauss-Seidel-Newton Projection algorithm and combine it with a restriction strategy. That makes it unnecessary to generate a priori all the paths. This algorithm may be further improved by exploiting the equivalence between the spatial price equilibrium on a general network and the network equilibrium. Computational results that we present in this paper demonstrate the efficiency of the proposed solution algorithms.     

THE REGIONAL MALL IN CANADA

Over the last three decades, regional shopping malls have become significant features of the Canadian urban landscape. They account for the largest concentrations of employment, retail sales, and trip destinations outside the central business district, and they reshape patterns of accessibility within communities. This article examines the number, economic role, location, and implication of these facilities, in Canada, and contrasts them with similar malls in the United States. By 7 986, there were 84 regional malls with more than 500 000 sq. ft. of space in Canada, and these malls accounted for 10 per cent of all retail sales.     

Determining Market Areas Captured by Competitive Facilities: A Continuous Equilibrium Modeling Approach

Many existing models concerning locations and market areas of competitive facilities assume that customers patronize a facility based on distance to that facility, or perhaps on a function of distances between the customer and the different facilities available. Customers are generally assumed to be located at certain discrete demand points in a two-dimensional space, or continuously distributed over a one-dimensional line segment. In this paper these assumptions are relaxed by employment of a continuum optimization model to characterize the equilibrium choice behavior of customers for a given set of competitive facilities over a heterogeneous two-dimensional space. Customers are assumed to be scattered continuously over the space and each customer is assumed to choose a facility based on both congested travel time to the facility and on the attributes of the facility. The model is formulated as a calculus of variations problem and its optimality conditions are shown to be equivalent to the spatial customer-choice equilibrium conditions. An efficient numerical method using finite element technique is proposed and illustrated with a numerical example.     

Geospatial modeling of pedestrian transportation networks: a case study from precolumbian Oaxaca,Mexico

Using accumulated cost surfaces and various pathfinding techniques within Geographic Information Systems (GIS) software, archaeologists and other spatial scientists have developed increasingly sophisticated models of human movement. Despite their utility, these approaches can be limited because standard GIS software cannot model movement (1) from many origins to many destinations or (2) without specific origins and destinations. Absent these capabilities, it is particularly difficult to model networks of movement over a given tract of land if you are interested in obtaining a more general sense of movement dynamics, not specific site-to-site patterns. In this paper, we present an innovative way of modeling past movement that generates both natural-looking networks and also indicates the degree of traffic that may have existed on any particular segment of those networks. The “From Everywhere to Everywhere” (FETE) model generates networks based on topography and landcover without requiring that origin and destination points be supplied in advance. We apply the FETE model to a case from the southern Mexican state of Oaxaca, a region that has extensive archaeological and ethnohistoric data sets that serve as a test of the efficacy of our technique. A comparison of the FETE output with known late precolumbian and early colonial movement corridors indicates that the method is effective and should be useful for modeling networks in other areas.     

Using the Public Open Space Attributable Index tool to assess children’s public open space use and access by independent mobility

This study examined associations between public open space (POS) attributes and children’s use, and independent mobility to, POS in Auckland, New Zealand. Overall 240 children aged 9–12 years and their parents/caregivers participated. Data were sourced from child travel diaries and parent telephone interviews. The Public Open Spaces Attributable Index (POSAI) assessed POS quality and quantity. Associations were examined between age, sex, ethnicity, parental licence of freedom score, and POSAI with: (1) child trips to POS and (2) independently mobile trips to POS. Children made a total of 68 trips to POS over a seven-day period; 35 of these were independently mobile. Child ethnicity was related to child trips to POS. Independent trips to POS differed by ethnicity and parental licence of freedom. This research utilised a new tool, the POSAI, to examine associations of POS use and independent mobility in children living in urban neighbourhoods.     

A Continuous Model of Traffic Flow

Traffic flow over continuous space is analyzed in an abstract one-dimensional city. A negative exponential attraction function, a quadratic exponential distribution of trip origins and a negative exponential distance-decay function are combined, and expressions are derived for traffic flow between arbitrary intervals in the city. With appropriate choice of the trip-origin function, the model may be applied to single and multipurpose trips. The resultant “contact fields” for individuals are briefly described, and the main results comprise algebraic approximations for aggregate flows between intervals. Numerical examples are given.