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How we Create our Vector Tiles

Our system generates vector tiles and stores them together as an MBTiles file.

What is an MBTiles file?

An MBTiles file is a file format and specification for storing vector tiles in the form of a single SQLite database. You can think of it as a filing cabinent that stores vector tiles in an efficient, organised way.

Our Vector Tile Pipeline

Our pipeline comprises three key steps, Extract, Create, and Join. In sequence, these three steps allow you to transform a set of vector datasets into a collective MBTiles file. We also have an additional step: Analyse. This step allows you to capture metrics about an MBTiles file's contents, useful for inspecting tile sizes and feature counts by layer.

Key Steps

The following sections provide details about the inputs required, process, and outputs generated for each step:

Validates JSON schema files, generates JSON STAC items, and prepare processing tasks for the create command.

Input

JSON schema files defining source layers and data schemas

Process

  • Validates schema definitions and checks for data updates
  • Determines which layers need processing by checking cache status
  • Creates STAC (SpatioTemporal Asset Catalog) metadata files for each layer
  • Separates layers into small and large processing queues for optimization

Output

JSON STAC items listing layers to process, cache status, and STAC metadata

Parses JSON STAC items, downloads the vector datasets, transforms each dataset's features, and combines them into individual MBTiles files.

Input

JSON STAC items describing individual datasets by layer

Process

  • Downloads source geospatial files (GeoPackage, Shapefile, etc.)
  • Converts to NDJSON format using OGR2OGR
  • Applies feature generalization and simplification
  • Generates MBTiles using Tippecanoe
  • Updates STAC metadata with processing results

Output

Individual MBTiles files for each layer

Combines multiple MBTiles files into one, and generates a tar.co archive file.

Input

Multiple MBTiles files (from Create command)

Process

  • Combines multiple MBTiles files into one
  • Generates a TAR.CO (Cloud Optimized TAR) archive
  • Creates tile index files for efficient access
  • Builds STAC catalogs for the combined dataset

Output

Combined MBTiles file, TAR.CO archive, index files, STAC catalogs

Generates a report detailing metrics about the generated MBTiles file.

Input

MBTiles files (local or remote)

Process

  • Examines tiles across all zoom levels (0-15)
  • Analyzes tile size distributions and identifies largest tiles
  • Calculates layer statistics (feature counts, geometry sizes, attributes)
  • Generates comprehensive performance metrics
  • Creates formatted reports using Mustache templates

Output

Detailed Markdown analysis reports