1.3.5. Interactivity

We now present you some functions that may be implemented into an interactive topographic map. The tools do not necessarily have to be implemented in a topographic map, but they are nice to have.

Have a look at the following example which contains a lot of possible interactive functions that can be implemented in an interactive map. Check out all the functions.

Interactive Topographic Map of Tuerlersee (Neumann 2002)

Did you really check all the functions? The following tools you should have been checked (Click here for more information)

Since we already discussed the navigation and the map layer control tools in previous chapters, we will say no more about these points. But we want to say a few words about some of the other functions.

In general, the following functions extract only the information that the user is already able to see in the topographic map. But the information is visualised in a more pleasing way.

Profile

With this tool you are able to draw the profile of an arbitrary polyline.

It is nice to have this function for interactive topographic maps since the topic of a topographic map is the topography. Of course the contour lines contain already all the information but it is nevertheless comfortable to get the difference in elevation at a glance. Especially for bikers or hikers this information can be of particular importance. Be aware that for being able to produce a profile you need the DTM (Digital Terrain Model - see Basic Cartographic Modelling of 3D Space) that belongs to the segment of the map that is visualised.

Profile (Neumann 2002)

Read out information and display it

The functions "select data to show on mouse-over" and "locate places" read information out of the map and displays it in two different ways:

• The attribute data (e.g. length of rivers, object-class of landcover, etc.) is displayed as text when moving the mouse over the corresponding objects.
• The places (villages and mountains) first have to be selected in a selection list and then the map is directly zoomed to the right position.

Displaying attribute values (Neumann 2002)

Locate places (Neumann 2002)

The function that gives information with on mouse-over effects are limited for topographic maps. You can only extract the information that is already visualised in the map (e.g. landcover types are distinguished with different colours, etc.). Of course it is not comfortable to extract the length of a river out of a screen map, but it is possible if you would have to do it.
You will see that in the subject of interactive thematic maps it is also possible to visualise attribute values that are not and never will be visualised directly in the map.