pmtiles 1.1.0

A library for parsing Protomaps PMTiles files. A single file archive format for storing raster or vector map tiles.

pmtiles

by Andrew Brampton (bramp.net)

Read PMTiles v3 archives stored locally or remotely.

GitHub | Package | API Docs

Usage

import 'package:pmtiles/pmtiles.dart';

/// A simple example of reading a PmTiles archive.
Future<int> main() async {
  // Open the archive from a file. HTTP URLs are also acceptable.
  final archive = await PmTilesArchive.from("/path/to/file.pmtiles");
  try {
    // # Metadata
    // Information about the archive is available in the header and metadata.
    print("Header:");
    print(archive.header);

    // Some interesting fields are also on the main tiles archive object.
    print("Type: ${archive.tileType}"); // e.g  mvt, png, jpg, etc.
    print("Compression: ${archive.tileCompression}"); // e.g gzip, brotli, etc.

    // The metadata is a embedded JSON object, as described here:
    // https://github.com/protomaps/PMTiles/blob/main/spec/v3/spec.md#5-json-metadata
    print("Metadata:");
    final prettyJson = JsonEncoder.withIndent('  ') // for clarity pretty print
        .convert(await archive.metadata);
    print(prettyJson);

    // # Tiles
    // To extract a tiles from the archive, you index them by a tile ID (which
    // can be converted to/from a ZXY coordinate).
    final int tileId = ZXY(4, 3, 2).toTileId();

    // To extract a single tile:
    final Tile t = await archive.tile(tileId);
    t.type; // e.g. mvt, png, jpg, etc.

    // The uncompressed bytes of the tile is available as a List<int>.
    t.bytes();

    // Equally if the tile is going to be reserved, you may leave it compressed
    // in the format that was used in the archive. See tiles.tileCompression above.
    t.compressedBytes();

    // To extract multiple tiles:
    final tiles = archive.tiles([tileId, tileId + 1, tileId + 2]);

    // This returns a Stream<Tiles> and Tiles will be returned as they become
    // available from the archive. This is optimised to reduce the requests
    // to the archive's backing store, leading to faster extraction.
    await for (final tile in tiles) {
      print("${tile.id} is available");

      // Again the bytes are available via:
      tile.bytes();
    }
  } finally {
    // Don't forget the close the archive once you are done.
    await archive.close();
  }

  return 0;
}

Development

Use melos bootstrap to install dependencies and link packages together.

Additional information

The specification is here https://github.com/protomaps/PMTiles/tree/main/spec/v3

LICENSE

BSD 2-Clause License

Copyright (c) 2023, Andrew Brampton

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this
   list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.

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