Byron Nakos

The Ability of Elementary School Children to Analyse General Reference and Thematic Maps

Physical maps with hypsometric tints, political maps with a monochromatic background, large-scale maps for younger students, and small-scale maps for older students, as well as maps with a limited number of thematic layers, are the predominant map forms found in elementary school textbooks in both Greece and Cyprus. The ability of elementary school children between Grade 3 and Grade 6 to analyse map content on these types of maps is investigated in a series of tests. The variables considered are map scale, complexity of background, number of thematic layers, and representation of land-forms. Results indicate the need for strategic use of different map forms in order to help students to develop the ability to analyse map content.

Children and Mapping

Children are exposed to maps from an early age. Map understanding progresses slowly and gradually from easy to difficult concepts. Theories of children’s spatial development, mainly deriving from psychological studies, have provided the theoretical basis for approaching the way children use maps. The results of three decades of theoretical and experimental studies offer insight into children’s thinking as to how they handle information while using maps, and also provide evidence regarding the development of concepts associated with the basic characteristics of maps. There is still a lot more to be said. Specialists on children and mapping persistently ask for map literacy, facing children as map users in the information technology era.

Three dimensional visualization of the built environment using digital orthophotography

In this paper, different ways of performing large scale mapping of built up areas are discussed. Emphasis is placed on large scale representation through digital orthophotographs as the visualization medium of the real world. In an application, the process of creating perspective views of an orthophotograph draped on the digital terrain model of the study area is described; these views include the blocks of the built environment as three dimensional objects. The cartographic product is derived from a pair of overlapping aerial photographs processed through photogrammetric and GIS software packages. Finally, the perspective view of the digital orthophotograph is assessed as a large scale visualization tool for the communication of spatial information.

Children's Choice of Visual Variables for Thematic Maps

Abstract The aim of this research is to examine how children use visual variables to represent nominal and ordinal data on thematic maps. Greek students from first (six- to seven-year old), second (seven to eight-year-old), and third grades (eight- to nine-year-old), without any systematic cartographic experience, were invited to participate in the composition of thematic maps at the stage of symbolization of various lists of items/attributes, using a specially designed software tool. The results revealed that many students, when making cartographic decisions, discovered basic principles of the application of visual variables in symbolization of nominal and ordinal data and expressed their preferences.

Critical Point Detection Using the Length Ratio (LR) for Line Generalization

Abstract This article presents a review of existing methods for the detection of critical points cited in cartographic and computer science literature. Moreover, a theoretical assessment of algorithm validity with regard to cartographic representation demands is carried out. A method for the detection of critical points using the length ratio (LR) index is introduced, based on geometric principles. Four lines (three geomorphologic and one arbitrary) selected from relevant studies are used to check the method. Finally, the LR index is used to compare the results of two line simplification algorithms (pointremove and bendsimplify) applied on five successive line simplification tasks on the coastline of a small island.

The SP‐displacement measure for assessing line simplification

In line simplification the overlay of the original and the derived line produces a certain number of polygons. The area of these polygons is related to the areal distortion between the original and the derived line caused by simplification. A new cartometric measure of displacement associated with each polygon (sp‐displacement) is introduced and tested, expressing the displacements caused by line simplification. Data consisting of ten coastlines are processed under successive simplification tasks over a wide range of tolerances by applying the Douglas and Peucker algorithm. All derived lines were overlaid with the original ones by applying a typical GIS function of union. The new measure is compared with other measures suggested in the literature.