Generation of thematic maps with wizards based on cartographic principles. The case study of OCAD Thematic Mapper.
1Tsorlini, A.; 2Hurni, L.; 3Sieber, R.; 3Gloor, T.; 5Klauser, H.
1ETH ZURICH, INSTITUTE OF CARTOGRAPHY AND GEOINFORMATION Email: email@example.com
2ETH ZURICH, INSTITUTE OF CARTOGRAPHY AND GEOINFORMATION Email: firstname.lastname@example.org
3ETH ZURICH, INSTITUTE OF CARTOGRAPHY AND GEOINFORMATION Email: email@example.com
3OCAD INC. Email: firstname.lastname@example.org
5OCAD INC. Email: email@example.com
Thematic maps are used in many sciences for the visualization of different spatially distributed phenomena related to a specific region of interest. They are used to illustrate a particular theme or to emphasize a special topic in an area or to portray spatial variations and interrelationships of geographical distributions. Thematic maps can portray physical, social, political, cultural, economic, or any other aspects of a city, state, region, nation or continent. As a consequence, the number of people, experts or not, who design thematic maps is getting larger, increasing also the necessity for correct thematic maps, something which is not always the case, especially for users who do not have the fundamental cartographic background. The basic elements needed for the construction of thematic maps are the statistical data used for the analysis and visualization of a theme in an area and the geometry or basemap features depicting this area. In order to create a correct thematic map, a user should follow a specific procedure, which although it may be simple, it can be also challenging if somebody has to follow the widely accepted cartographic rules in the construction of the maps. In this procedure, there are particular steps which are connected and influence one another. For example, the statistical data should be selected, analyzed and processed according to the given theme of the map; the proper visualization method should be selected according to the geometry features and the final visualization of the theme influences the basemap and the items depicted on it. All these parameters should be combined in such way that the final map will be complete and readable. In this project, we analyze the most important visualization methods mentioned in cartographic literature in accordance with the different types of statistical data and geometry features possible to be used when constructing a thematic map. As a result of this analysis, a decision scheme is designed, describing analytically the different steps of the whole procedure and showing the different choices which can be made by a user, to visualize the selected theme on his map. The novel part of this scheme is that if the input data or a selection made in a previous step does not fulfil the specific criteria set, based on cartographic principles, new, more suitable options are provided through the scheme, together with information messages, to help the user to decide what to choose. Moreover, if a user insists on creating a map departing from the cartographic rules, he can still do it following this scheme, but warning messages and hints will appear during the procedure, to inform him that the selected visualization method is not the proper one. Based on this analysis, a new software, named OCAD Thematic Mapper, is developed jointly by OCAD Inc., a company dealing with software development for map production, and the Institute of Cartography and Geoinformation at ETH Zurich. OCAD Thematic Mapper will provide its users the opportunity to create correct thematic maps through a guided procedure in form of Wizards. These Wizards were designed in a simple, clear and comprehensible way, giving the opportunity to the user to create his own map deciding about its appearance while he will be advised and directed by them to select the most suitable visualization method according to his data for the construction of his thematic map. In this software, the whole cartographic procedure for the construction of thematic maps is analyzed in detail and organized in such a way that helps the user to create a correct thematic map in a user-friendly way, without having to worry about the complexity of the procedure and the correctness of his choices on the construction of the map. This is also the most important benefit of this software in comparison to other existing software developed to create thematic maps.
thematic maps; cartographic principles; wizards