Utility functions for map-tile calculations and caching directly in a PostGIS database. The functions here are designed to support a variety of dynamic tiling tasks, including:
- Getting the correct extents and CRS information for a given tile
- Setting feature visibility, simplification, and clustering based on zoom level
- Finding containing tiles for a given feature
Also included are tables and functions supporting a simple tile-caching system backed by a PostGIS table (similar to an MBTiles SQLite database). Using triggers + the utility functions above, this will support simple expiry and updating, easing management of a large tile cache.
This software is heavily inspired by Mapbox's postgis-vt-util.
However, like the morecantile Python library, it supports
multiple TMS definitions, making it suitable for use in planetary as well as Earth-based applications.
Simply run the SQL contained in this repository against your PostGIS
database (v11 or greater likely needed). This will create functions
in the tile_utils namespace. If the appropriate files are read in,
the tile_cache schema will be defined as well.