Workflow management and generalisation services

1. Motivation In the domain of map production two trends are currently noticeable. On the one hand, a continued automation of the processes for derivation of traditional, analogue paper maps, and on the other, functions for delivering dynamic maps in web mapping and mobile applications e.g. on PDAs. In these scenarios identical geo data of one reference scale provides the basis for the specific maps. The derivation is based on generalisation employing different functions. To provide this functionality independent from operating system and programming languages the concept of web services are applied to the field of automated generalisation (Neun et al., 2006; Burghardt et al., 2005a). These allow the integration of external generalisation functionality in existing GIS and map production systems, without changing the developed production runs. Ideas about web services are discussed on the international generalisation workshops of the “ICA Commission on Generalisation and Multiple Representation“. An important scientific question under the topic of cartographic generalisation is the automated selection, chaining and parameterisation of generalisation functions. Until now there are only a few scientific publications treating this problem. One reason is that experiments can only be carried out with an extensive set of generalisation functions, often not available on one platform. Worth mentioning is the AGENT approach (Ruas, 1999; Barrault et al., 2001), whereby the orchestration is carried out with help of meso agents on the basis of cartographic constraints. Further approaches make use of several optimisation methods (least square adjustment, energy minimisation, simulated annealing) to combine different generalisation functions. The development of generalisation services solves the problem of the availability of an extensive set of generalisation functions. The research presented in this paper will focus therefore on the usage of workflow management systems for orchestration and combination of different generalisation services. This proposed approach is currently being implemented in axpand, the cartographic GIS of Axes Sytems (Axes Systems, 2006).

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