Multiple representational databases and navigation map design

Abstract

The invention of the computer is certainly one of the most important events affecting the everyday life in 20th Century. This event have triggered a new restructuring and renovation process in each sector therefore work habits and operating methods changed and developed for each disciplines. Geodesy and Photogrammetry engineering has been affected from this change as well as the other disciplines.As a result of stated change, classical map design and production methods are postponed by the use of the computer aided design technologies additionally new studies have been executed to achieve full automated generalization. On the other hand, since the amount of the data increased as a result of the use of these technologies, new studies have been conducted to develop new database and database management system approaches for managing the collected data. Finally, the effective use of Geographical Information Systems (GIS) has accelerated these developments lived in spatial data sector. Generalization is certainly one of the most important issues of the cartography which is the science and art of visualization of world reality on paper, screen or similar media. Geographic Information Systems are the most effective communication methods of world reality recently. Moreover GIS is the product of inter disciplinary solidarity and cooperation. As a result of GIS requirements for multiple aimed production and updating data regularly researches executed on automated generalization become effective. Furthermore representations with different aims, scale and capabilities have come out, because each user contributed to their work in GIS, to represent their expertise and specific information by using the rules and the methods. Besides researches on automated generalization, data base design for multiple representations with very huge amount of data became a current problem. Thus, multiple representations and multiple representational databases (MRDB) became significant component of GIS. Navigation is a fundamental human activity and an integral part of everyday life. People have navigated themselves with no maps; technological developments facilitated navigation by providing paper maps. Nowadays, advanced navigation systems have been developed, integrating positioning and communication techniques, digital mapping, computer and handheld device technologies. Navigation is specified according to its application area – such as aircraft, marine, nautical, personal, and car navigation etc. Although these navigation types have significant differences because of their application dependent constraints and aims, the demand for wayfinding lies at the core of them all. Map design for navigation purposes should be considered in terms of two different approaches; base map which will be used as geometric layout and the map used as user interface. The map on which spatial analysis will be executed, geometric layout, needs high accuracy and less generalization while the other one is highly generalized in terms of application. Therefore while designing these maps particularly geometry of the road networks should be strictly preserved and other related and required objects should be generalized and symbolized for navigation. In this paper, multiple representational databases, which are a new approach for data organization problem of GIS, were examined with its all components and benefits. In this concept, this database structure was sampled with its main components in terms of map design for car navigation. In this scope, junctions, which are the most complex structure of the roads, were considered as a problem and different design models were examined for navigation maps. Key problem areas for navigation are those parts of the network where a change in topology occurs with a change in scale. A divided highway with a two-line representation will be represented by a single line at a sufficiently small scale and, with continued scale change, may even be completely eliminated. Such changes can be expected to produce many problems to the navigating user, and hence to the cartographer. Fundamentals of multiple representational databases are developed for the urban road data, where the significant transformations in junctions and roadways are identified and tracked. Tools for formalizing and handling multi-scale representations are presented. As a result, the fundamental infrastructure for the use of multiple representational databases in navigation map design applications was formed in this paper.

Özet

Coğrafi Bilgi Sistemleri (CBS) uygulamalarında; farklı disiplinlerden, farklı amaç ve istekteki kullanıcılar görev almaktadır. Bu da söz konusu uygulamalarda kullanılan verinin organizasyonunu güçleştirmekte ve veri yoğunluğu, çözülmesi gereken bir sorun olarak gündeme gelmektedir. Diğer taraftan uygulamalarda aynı yeryüzü fiziksel gerçekliğinin farklı amaç ve ölçeklerde modellenmek istenmesi de aşılması zor olan sorunları gündeme getirmektedir. Bu tür sorunların aşılması amacıyla yapılan çalışmalarda yeryüzü gerçekliğinin çoklu gösterimi ilkesini temel alan farklı bir verita-banı yaklaşımı ortaya atılmıştır. Çoklu Gösterim Veritabanları olarak adlandırılan bu yaklaşımda, uygulamaya yönelik farklı amaç ve ölçekteki ürünlerin, tek bir veritabanından otomatik genelleştirme ile türetilmesi ve daha sonra güncelleştirilmesi amaçlanmaktadır. Bu çalışmada ilk olarak, günümüzde kartografların önemli çalışma ve araştırma alanlarından biri olan genelleştirme konusunda genel bilgiler verilmiş ve sonrasında CBS uygulamalarının önemli bir sorunu olan veri organizasyonuna yeni bir yaklaşım getiren çoklu gösterim veritabanları, tüm bileşenleri ve sağlayacağı avantajları ile ele alınmıştır. Bu amaçla yapılan çalışmada araç sürücülerinin bir sistem dahilinde yönlendirilmesini amaçlayan araç navigasyon sistemlerinde kullanılan yol haritalarının tasarımı, çoklu gösterim veritabanları perspektifinde incelenerek söz konusu veritabanı yapısı temel bileşenleri ile örneklendirilmiştir. Bu kapsamda yol ağlarının, algılanması en zor parçalarını oluşturan kavşak yapıları ele alınmış ve navigasyon haritaları için uygun tasarım modellerine yönelik bir araştırma yapılmıştır. Bu amaçla, farklı ölçek ve çözünürlük seviyelerinde kullanılan kavşak ve yol ağı gösterimleri baz alınarak farklı gösterim seviyeleri belirlenmiştir. Sonuç olarak bu çalışma ile çoklu gösterim veritabanı yaklaşımının navigasyon uygulamalarında kullanılmasına yönelik temel altlık hazırlanmıştır.