Influences on the appliance of generalisation within “Neocartography”
In a previous post I described in how far the modern technological trends of “Web 2.0” could have produced a new kind of generalisation, called “Neogeneralisation”. According to terminologies it became clear that the term “Neogeneralisation” is related to modern technological developments as well as a community driven appliance of generalisation, which are currently just very slightly implemented.
Independent from these trends, generalisation is a fundamental process which is already applied to applications of “Neocartography”, which are for example “Maps 2.0” as well as the derivation of maps from “volunteered geospatial information”. For being able to analyse the basic appliance of generalisation within these contexts, I want to prepend in this post a description of the basic constraints that influence the way generalisation is applied within the field of “Neocartography”.
It is possible to identify three basic constraints which can be summarised by the following questions:
- Who is applying generalisation?
- How is generalisation applied?
- What output is generated when generalisation is applied?
The question on Who is applying generalisation is a very new influencing factor and it is strictly bound to the constraints of “Web 2.0”. More and more non-experts are able to make individual maps or participate to map making processes in a community. Therefore it is only logical to take also into account if an geoinformation expert or even a cartographer, who has solved an education on working with map making, or if a non-expert who is just interested in map making is applying generalisation. As the group of non-experts is very heterogeneous it is not possible to imply any special previous knowledge about cartography generally or about generalisation in particular to this group of people. According to the schema of Shea & McMaster…there is a high diversity in the realisation why, in the understanding on when and in the competence on how to apply generalisation.
The question on How generalisation is applied distinguishes between manual and automatic generalisation. Many different schemas for distinguishing the generalisation operators were already made but basically I like the categories of the AGENT-project which differ between the schematic transformation and the geometrical transformation of features. In the field of “Web 2.0” the final map visualisations are mostly rendered automatically by pre-defined styling parameters.
The question on What output will be generated can be divided into two areas. On the one hand generalisation can be applied to generate analogue (printed) map output and on the other hand it can be applied to generate digital map outputs. Digital maps can also be separated into the sub elements static, scalable and interactive. A static digital map has fixed map display where the author always knows what will be finally displayed to the map user. The final visualisation of a scalable map has many different occurrences as the user can adjust the map display within the extents the author has pre-defined. An interactive map is always a scalable map with the additional possibility for overlaying additional informations like mash-ups what generates additional requirements to the base map. All these types of output exist within cartography of “Web 2.0” and it is obvious that a map maker has to observe the different characteristics of the aimed output when he/she applies generalisation. These are just the basic output characteristics but taking also the continuative characteristics into account would go too far for this description, but necessarily they have to be observed in practical implementations.