Content Compatibility

Some combinations of layers, maps scales, and map types are bound to lead to cartographic faux-pas. Thus, we developed rules that try to exclude combinations that would lead to low cartographic quality. But, it is impossible to predict all the possible combinations that the users could make, thus, many of there rules are interpreted as wanring and encourage the users to think about the validity of their choices. A few rules lead to plain errors and require a change in the parameters, either the layer selection or the map type most of the time.

Cartographic content restrictions

Based on map type

This geoportal manages four map types: general-purpose map, physical map, political map, and thematic map. Different map types require different content and rules, which is why you need to assign a map type to the map you are creating.

  • General-purpose maps focus on displaying the main feature of an area, both physical and man-made. Thus only a couple of thematic layers are allowed for this map type.
  • Physical maps focus on displaying the topographic features of the landscape, such as mountains, rivers and lakes. Thus, thematic layers are forbidden and physical layers pertaining to hydrology and other physical topics are required.
  • Political maps focus on showing administrative boundaries (national, regional, and/or local) and labelling places (cities, regions, countries, etc). Thus, thematic layers are forbidden and there must be at least a administrative border layer.
  • Thematic maps focus on a specific topic and display thematic data, such as statistics for administrative units or pollution values for a stream. Thus, thematic layers are required and the natural and cultural layers should not be more than 5 combined.

Based on map content

Generally, maps have a certain amount of information, but not too much either. Additionally, they have a main topic and the scales of the layers are comaptible with the scale of the map.

  • Restrictions about the number of layers allowed: at least 2 and no more than 12. This was defined as sensible default value based on the examination of several national geoportals nand their content, estimating what would too much information for a single maps based on the content usually offered by the geoportals.
  • If the user does not set one or two main layers for the map, there will be a reminder.
  • Scale mismatches are also brought to the attention of the users.
  • Risk of overlaps between polygonal layers are also checked: e.g. landuse with a thematic layer.