COMTILES: A CASE STUDY OF A CLOUD OPTIMIZED TILE ARCHIVE FORMAT FOR DEPLOYING PLANET-SCALE TILSETS IN THE CLOUD

Abstract. The container formats commonly used for managing map tiles, such as MBTiles and GeoPackage, were originally designed with only POSIX filesystem access in mind. This makes these file formats inefficient to use in a cloud native environment, especially in combination with large tilesets. The Cloud Optimized GeoTIFF format solves the problem of providing large satellite data in the cloud, creating a new category of so-called cloud optimized data formats. This type of format allows geospatial data to be deployed as a single file on a cheap and scalable cloud object storage such as AWS S3 and accessed directly from a browser without the need for a dedicated backend. Based on the concepts of the COG format, this contribution proposes a new cloud optimized file format called COMTiles, specially designed for planet-scale tilesets. This format has the potential to simplify the deployment workflow of large tilesets in a cloud-native environment, while simultaneously reducing the hosting costs. In comparison to PMTiles, another cloud-optimized tile archive solution, COMTiles can reduce the number of transferred data and the performance of decoding portions of the file. COMTiles also adds support for different coordinate systems.