POSSIBILITY AND CONSTRAINT PARAMETERS FOR AUTOMATED GENERALIZATION OF MULTI – SCALE BASE MAPS

Map generalization plays an important role in map-making process. Map generalization depends on many factors such as purpose, geographic scope, thematic, map scale… and therefore it remains one of the challenging issues in Cartography. This paper discusses the constraint parameters and process of cartographic generalization from map data at 1:2000 to map data at smaller scale such as 1:5.000, 1:10.000, 1:25.000, 1:50.000 and 1:100.000. These constraint parameters are indentified by applying cartographic principles and using experimental procedures with generalization toolset in ArcGIS 10. Defined constraint parameters are then put in cartographic generalization for base maps of Ho Chi Minh City in order to verify their rationalities.Research result shows that, using right parameters and GIS cartographic generalization tools could provide good way to generalize and create base map products fast, efficient and reasonable. It also provides useful information for further research in automated map generalization and in creating multi-scale, multi-purpose map database.

Comparative Study of Algorithms for Automated Generalization of Linear Objects

Automated generalization, rooted from conventional cartography, has become an increasing concern in both geographic information system (GIS) and mapping fields. All geographic phenomenon and the processes are bound to the scale, as it is impossible for human being to observe the Earth and the processes in it without decreasing its scale. To get optimal results, cartographers and map-making agencies develop set of rules and constraints, however these rules are under consideration and topic for many researches up until recent days. Reducing map generating time and giving objectivity is possible by developing automated map generalization algorithms (McMaster and Shea, 1988). <br><br> Modification of the scale traditionally is a manual process, which requires knowledge of the expert cartographer, and it depends on the experience of the user, which makes the process very subjective as every user may generate different map with same requirements. However, automating generalization based on the cartographic rules and constrains can give consistent result. Also, developing automated system for map generation is the demand of this rapid changing world. <br><br> The research that we have conveyed considers only generalization of the roads, as it is one of the indispensable parts of a map. Dehradun city, Uttarakhand state of India was selected as a study area. The study carried out comparative study of the generalization software sets, operations and algorithms available currently, also considers advantages and drawbacks of the existing software used worldwide. Research concludes with the development of road network generalization tool and with the final generalized road map of the study area, which explores the use of open source python programming language and attempts to compare different road network generalization algorithms. <br><br> Thus, the paper discusses the alternative solutions for automated generalization of linear objects using GIS-technologies. Research made on automated of road network generalization, which is summarized in this paper, was conducted in IIRS, Dehradun, India.