Kartansorting

Kartansorting is a technique in computational cartography used to determine the order in which map features are processed, drawn, or simplified. By assigning a single priority value to each feature that combines geometric, topological, and thematic attributes, kartansorting aims to optimize rendering performance while preserving map readability.

The term appears as a descriptive concept in discussions of advanced map pipelines and is derived from kartan, a root meaning map in several languages, and sorting. It is not a single standardized algorithm but a family of approaches that share the same goal of ordered processing.

In practice, a kartansorting score S is defined as a weighted sum of factors such as geometric complexity, feature size, connectivity, thematic importance, and viewport relevance. Features with higher scores may be drawn earlier or later depending on the desired balance between speed, overdraw, and label placement.

Applications include incremental vector tile rendering, multi-resolution generalization, and interactive maps where an implied draw order improves perceived performance and reduces clutter.

Limitations include the need to choose weightings, potential bias toward certain feature types, and additional computational cost, with results sensitive to viewport and scale.

Related concepts encompass painter's algorithm, z-ordering, and modern map generalization techniques.