maxzoom

Maxzoom is a parameter used in digital mapping to denote the highest zoom level for which tiles in a dataset or tile service are provided. It defines the finest level of detail that a map source can deliver and is typically paired with a corresponding minimum zoom, minzoom, to establish an available zoom range.

In practice, maxzoom appears in several formats and systems that support tiled maps. TileJSON, MBTiles metadata, and map style specifications often include maxzoom to indicate the upper bound of the tile set. Map rendering libraries use this value to determine which tiles to request and cache. When a user zooms in beyond maxzoom, behavior varies by implementation: some clients stop requesting higher-zoom tiles, while others may fetch a higher-zoom tile by resampling from a lower-zoom tile or return an error if tiles at that zoom are not available.

The value of maxzoom is independent of the map’s projection and is determined by the dataset’s creation or hosting configuration. Web mapping commonly uses zoom levels from 0 up to a practical maximum such as 18, 20, or 22, depending on data resolution and performance considerations. A source or layer can enforce its own maxzoom to control tile generation, rendering performance, and cache efficiency.

Understanding maxzoom helps in configuring tile servers, optimizing tile pyramids, and setting user expectations for detail at high zoom levels. It is distinct from but related to minzoom, which defines the lowest zoom level available for a given source.