  Label placement in maps is a very challenging task that is critical for the
overall map quality. Most previous work focused on designing and implementing
fully automatic solutions, but the resulting visual and aesthetic quality has
not reached the same level of sophistication that skilled human cartographers
achieve. We investigate a different strategy that combines the strengths of
humans and algorithms. In our proposed method, first an initial labeling is
computed that has many well-placed labels but is not claiming to be perfect.
Instead it serves as a starting point for an expert user who can then
interactively and locally modify the labeling where necessary. In an iterative
human-in-the-loop process alternating between user modifications and local
algorithmic updates and refinements the labeling can be tuned to the user's
needs. We demonstrate our approach by performing different possible
modification steps in a sample workflow with a prototypical interactive
labeling editor. Further, we report computational performance results from a
simulation experiment in QGIS, which investigates the differences between exact
and heuristic algorithms for semi-automatic map labeling. To that end, we
compare several alternatives for recomputing the labeling after local
modifications and updates, as a major ingredient for an interactive labeling
editor.

Computational Geometry;Artificial Intelligence;Human-Computer Interaction