Generating and mapping population density surfaces within a geographical information system

Abstract

The spatially discontinuous choropleth map is a poor representation of the underlying continuous distribution of population density. A possible alternative is to derive dasymetric maps at a fine spatial resolution by making use of satellite imagery in a geographical information system. However, there are cartographic problems when these maps are displayed and further processing is needed in order to obtain approximations to a continuous density surface. Isarithmic maps of these density surfaces retain a high degree of spatial accuracy while providing pleasing and highly adaptable presentations.

The methods used to generate dasymetric and isarithmic maps are readily implemented in most raster based geographical information systems. For example, the classification of remotely sensed imagery, the subsequent processing and integration of data, and most of the cartographic display, were all undertaken in this work using the low cost IDRISI GIS that operates on standard IBM PC compatible hardware.     

Maps on Acid: Cartographically Constructing the Acid Rain Environmental Issue, 1972–1980

This article traces how maps aided the conceptualization and ensuing debate over one of the first inherently spatial and multiscale environmental issues, acid rain. Through interviews with early acid rain ecologists and a critical cartographic analysis of printed maps, we show that mapping was central for constructing this environmental issue. Rather than static representations of a scientific reality, acid rain maps were interconnected and relational processes that operated within political and economic discourses. Accordingly, we suggest that increased critical engagement and participation with the process of mapping can productively aid dialog on many issues, including other current multiscale environmental issues, such as climate change.     

Map Use by Adults with Visual Impairments

In this paper we summarize five experiments that were designed to investigate how tactile maps contribute to the cognitive maps of people with visual impairments. In two experiments we demonstrated that tactile maps can contribute to peoples' ability to learn a route through an unfamiliar area. From the results of two further studies, we argue that compared to people with sight, people with visual impairments have greater difficulty encoding information from a map. We considered this directly in a fifth experiment by investigating how people with visual impairments search and learn a map. We found that they used less efficient strategies than people with sight. We conclude that tactile maps are an important source of geographical information when people need to learn about new environments, but we also point out that to benefit most from tactile maps people need to encode the map information as effectively as possible. As people with visual impairments do not always use the most appropriate encoding strategies we suggest that tactile map users might benefit from greater experience and training in map encoding strategies.     

TOWARD A GEOGRAPHY OF THE INDUSTRIAL ESTATE∗

Geographic Software Reviewed in this article:

APPLEPIPS

IBM EDUCATIONAL SOFTWARE SERIES: EARTH SCIENCE SERIES. Moisture in the Atmosphere, Hydrologic Cycle, Surface Water Ground Water

MINI-MAX

MULTIMAP. Barry R. Cohen. Planning Data Systems

WORLD GEOGRAPHY SERIES, U.S. GEOGRAPHY QUIZ, U.S. GEOGRAPHY ADVENTURE     

THE GEOGRAPHY OF MASTODON EXTINCTION

Geographic Software Reviewed in this article:

LIFE TABLES and the LESLIE MATRIX. CONDUIT

MENTMAP2. Lawrence W. Carstensen Jr.

PC-MATLAB, Version 1.0. The Math Works, Inc.

QUICKMAP, version 1.0. Sammamish Data Systems, Inc.

SYSTAT: THE SYSTEM FOR STATISTICS, Version 2.1, Systat Inc.

USA DISPLAY. Instant Tecall     

Placing dots in dot maps

Dot mapping is a cartographic representation method to visualise discrete absolute values and their spatial distribution. To achieve this, dots equal in size and represented value are used. According to the dot value, a certain number of dots are used to depict a data value. These dots usually form dot clusters. The data value needs to be rounded to a multiple of the dot value. It is possible to roughly determine the visualised data value by counting the dots and multiplying this number with the dot value. As there are many parameters – dot size, dot value, map scale – to consider when designing a dot map, the manual way is very complex and time consuming. This paper presents a method to automatically create a dot representation of a dot map from given statistical data that needs no cartographic expertise. The dot representation may be combined with other elements, such as a topographic background, to form a complete map. So the algorithm can easily be integrated into the map design process. The paper refines the basic approach of automated dot mapping published earlier. The dot placement and arrangement have been improved compared to the basic method.     

Excel与MapGIS结合在地质制图中的应用

采用MapGIS软件绘制地质图件时,经常遇到需要批量输入点线等数据问题,如果直接逐个输入,不但效率低下,且容易输错,利用Excel的编制函数功能编写MapGIS明码文件,来说明如何实现MapGIS点线文件的批量输入,使地质图件的绘制更加快速、准确、高效。     

清单式管理在地震应急技术保障中的应用研究

地震是一种突发性强和破坏性大的自然灾害,重特大地震的发生往往致使较重的人员伤亡和财产损失。科学制作并合理利用应急技术产品是提升抢险救援效率的有效措施,可以有力支撑指挥层级快速决策与应急指挥。以四川长宁"6·17"地震中的应急技术保障工作为参鉴,结合当前常用应急监测技术手段,全面梳理应急技术保障产品在实践应用中的常态问题。并在此基础上,引入"清单制"管理思维,从何种阶段制作哪类产品,哪类产品需要哪些要素上进行细化构思,建立地震灾害应急技术保障产品清单,从管理模式上规范技术保障机制,促使地震应急技术支撑有力并且有序,切实提升震后应急处置效率。     

Digital geoscientific maps: A priority program of the German Society for the Advancement of Scientific Research

In October 1984, the German Society for the Advancement of Scientific Research (DFG) began a 5-year Priority Program to develop a new general concept for computer-assisted field work and construction, production, and evaluation of geoscientific maps with contents either from a single geodiscipline or from various disciplines, as a part of a future geoscientific information system.     

REVIEWS OF GEOGRAPHIC SOFTWARE

Geographic Software Reviewed in this article: APPLEPIPS IBM EDUCATIONAL SOFTWARE SERIES: EARTH SCIENCE SERIES . Moisture in the Atmosphere, Hydrologic Cycle, Surface Water and Ground Water. MINI-MAX MULTIMAP . Barry R. Cohen . Planning Data Systems WORLD GEOGRAPHY SERIES, U.S. GEOGRAPHY QUIZ, U.S. GEOGRAPHY ADVENTURE