SOLVING A THREE-DIMENSIONAL URBAN ACTIVITY MODEL OF LAND USE INTENSITY AND TRANSPORT CONGESTION*

ABSTRACT Recent developments in combining input-output and transportation planning models have made it possible to construct realistic comprehensive urban and regional activity models of land use intensity. These models form the basis for a rigorous approach to studying the interactions among urban activities. However, efficient computational solution methods for implementing such comprehensive models are still not available. In this paper, an efficient solution method for a nonlinear programming urban systems model is developed by combining Evans's partial linearization technique with Powell's hybrid method. The solution algorithm is applied to a small but realistic urban area with a detailed transportation network.     

MONOPSONY AND PLANT LOCATION IN A THÜNEN LAND USE MODEL*

ABSTRACT. Previous work has developed a method for studying noninfinitesimal operational units, called “plantations,” with the Thüen model. In that model, increasing returns to scale generate large operational units, but the potential market power conferred by the scale economies is sidestepped as an issue. The present work introduces finite supply elasticities and examines their locational impacts. The profit-maximizing monopsonistic plantation is smaller, and the shipment distance for its processed output is shorter, than for a comparable competitive plantation. The present approach does not involve spatial competition strategies.     

LAND USE AND LAND COVER IN EASTERN CHINA: A LANDSAT ANALYSIS

Landsat imagery is a valuable source of information about the land use and land cover of inaccessible areas. In this study, the objective was to compile a map of eastern China, with particular emphasis on agricultural activity, from enhanced Landsat imagery using the diazo and density slicing techniques. Area measurement of major land uses was based on the land-use interpretation map, but because of the lack of ground verification it was necessary to turn to other sources of published and unpublished information as a control.
L'objectif de cette étude est la compilation d'une carte géographique de l'Est de la Chine, avec accentuation particulière des activités agricoles. Comme les images Landsat sont souvent la source unique d'information sur la végétation et l'utilisation de terrains inaccessibles, cette carte a éte cornpilée à l'aide d'images Landsat agrandies par les techniques diazo et density slicer. Les mesures des surfaces des régions principales sont celles de la carte d'interprétation de l'utilisation des terres. Faute d'une méthode de calibrage, il a fallu accepter les données de sources secondaires publiées et nonpubliées comme base de contrôle.     

LAND USE IN THE PRESENCE OF AN ATMOSPHERE EXTERNALITY,WITH AND WITHOUT CORRECTIVE TAXES*

ABSTRACT. Total cleared area in a von Thünen land-use model drives an atmosphere externality which depresses agricultural productivity uniformly throughout the region. Exogenous events that encourage clearance and use of a larger cultivated area (output price or population increase) exacerbate the externality. Imposition of a simple, corrective tax on land rents does not reverse these patterns but does mitigate the increase in the externality and leaves cultivators with higher incomes than they would obtain without the tax. We examine an optimal tax on land rents, designed to maximize the social value of land rents in the region, and an output tax.     

A PUBLIC UTILITY APPROACH TO LAND USE

Escalating legal confrontations between private enterprise and government over land use controls are raising the costs of land development and slowly eliminating the potentials for reasonably priced family housing. Equally important, these confrontations are beginning to have more and more of the negative aspects of public utility control processes without any of the associated benefits. Now would seem to be an ideal time in which to review the “public utility” approach to land use controls since it can offer many more benefits than current control systems, while balancing society concerns and private developers' fair return objectives.