Atlas Mapping in the 21st Century

Atlases are changing. The paper paradigm of maps and atlases has pervaded recent cartographic history. By nature that paradigm serves, as well as defines, a specific audience in terms of use and presentation. In the lab and at the printing press, the paper paradigm demands certain design and production flows that will drastically change through evolutions in data structures, mapmaking techniques, and presentation methods. Technological transformations in mapping influence much of this change. The implications for the creation and distribution of atlases are significant. With that in mind, this paper addresses a number of issues that relate to the technological evolution of atlases from paper to digital products: the distinction between paper and digital products and services and the implications of that distinction for atlas design—particularly for web-based services; facilitating data and its application to the evolution of map/atlas products; and a redefinition of "atlas" and the "audience" for an atlas.     

Delaunay Triangulations and Stereographic Projections

After describing Delaunay triangulations of vertices on a sphere and in a plane, we prove that every Delaunay triangulation of vertices on a sphere corresponds to the Delaunay triangulation in the plane of any stereographic projection of the spherical triangle vertices. We then exploit this correspondence to build robust algorithms for Delaunay triangulations in the plane or on the sphere. We also describe a collection of "fisheye" conformal transformations of the sphere that are the composition of one stereographic projection with the inverse of another stereographic projection.     

A Structure Recognition Technique in Contextual Generalisation of Buildings and Built-up Areas

Abstract

A structure recognition technique is presented that can be employed for contextual building and built-up area generalisation in medium-scale topographic maps. Owing to various spatial configurations, a contextual mechanism is necessary to achieve acceptable results in cartographic generalisation. Spatial structures are usually implicit in data, and advanced analysis and processing methods are required to detect them. This technique is based on auxiliary geometric data structures and spatial analysis methods. A case study is performed with a topographic data set, using an interface developed in an object-oriented geographic information system (O-O GIS). The proposed approach was found to assist and improve automation.     

Generalization Services on the Web—Classification and an Initial Prototype Implementation

Much progress has been made in the field of web-based cartography through standards developed by the Open Geospatial Consortium (OGC). While automated access and presentation of cartographic data have been defined, the services for automated generalization are yet to be standardized. This paper aims to show advantages of applying the service concept to generalization and suggests several classification schemas of generalization services at different levels of granularity. A detailed explanation of a real implemented Generalization Service is provided. We show how software developers can make their generalization functionality available as a service and how these services can be accessed dynamically. For the implementation, the open source Java Unified Mapping Platform (JUMP) was extended to work as a framework for generalization. Generalization services could be used in different application scenarios, for instance as a middleware component extending a web map service with adaptive zooming or as stand-alone services supporting the production of topographic maps by national mapping agencies. They may also allow the development of a common research platform, where researchers would have access to a common generalization framework.