gdal2mbtiles

gdal2mbtiles - gdal2tiles with mbtiles support

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• this is an adapted version from [https://github.com/mj10777/mapmbtiles] where

  • gdal2mbtiles.py,globalmercator.py and mbtiles.py
    • have been combinded into one file gdal2mbtiles.py

• goal is that gdal2mbtiles.py will run

  • in the same way as gdal2tiles.py, but with mbtiles support
  • that mbtyles task can be run from small pythons scripts
    • using the functionality taken from the Mapbox and Landez projects

• final goal:

  • to submit gdal2mbtiles.py to the GDAL-Project

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• the Map Tile Cutter is based on the original work of:

  • Klokan Petr Pridal [email protected]
  • the original project source can be found at [http://code.google.com/p/maptiler]
    • the source code used here was taken from the maptiler_1.0.beta2_all.deb
      • this source is newer than the source in the git-repository
    • to my knowlage the support for this project has been disscontinued in its Open-Source form.

• some of the Mbtiles creation logic came from the Mapbox project:

  • the original project source can be found at [https://github.com/mapbox/mbutil]
    • much of this code however differs

• some of the Mbtiles funtionality came from the Landez project:

  • the original project source can be found at [https://github.com/makinacorpus/landez]
    • much of this code as been adaped to read/write directly to the mbtiles files
      • beforhand it used a cache that was filled by another class

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• The main goal was to adapt the gdal2tiles.py to also support the creation of a mbtiles Databases

  • gdal2tiles.py has been renamed to gdal2mbtiles.py to avoid conficts with the original gdal version
  • the basic functionality has otherwise not been changed
    • tilemapresource.xml : is now written correctly (x and y values were switched)
    • all of the y tiles are created first (each x directory is filled compleatly, before the next is created)
      • this makes it quicker to resume after an interuption

• The created mbtiles Databases are based on the same logic used in the geopaparrazi project:

  • [https://github.com/geopaparazzi/geopaparazzi/wiki/mbtiles-Implementation]
  • it uses tiles as a view and not a table
  • it will check for blank images (all pixels have the same RGB value) and store this only once

• When install on linux, a soft-link called gdal2mbtiles will be created

  • this can be called with the same paramaters as gdal2tiles.py
  • when called with --mbtiles the [output] parameter will be ignored
    • in the directory as the image: a image_name.mbtiles will be created
    • the created tiles will then be stored in a mbtiles Database and NOT as a tile-directory
  • when called with --mbtiles_from_disk
    • the [input_file] parameter will be used as the tile-directory
    • the [output] parameter will be used as the file-name for mbtiles
      • the tiles of the tile-directory will be imported into the mbtiles file
  • when called with --mbtiles_to_disk
    • the [input_file] parameter will be used as the file-name for mbtiles
    • the [output] parameter will be used as the tile-directory
      • the tiles of the mbtiles will be exported into the tile-directory

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In the samples directory, there are some python scripts that use this project when installed

• they are based on the functionality taken from the Landez project
  • importing all or a portion of one mbtiles to another
    • this can be used to convert a table based mbtiles to a view base mbtiles
      • this will also check for blank images
  • filling a mbtiles from a WMS-Server
  • exporting all or a portion of one mbtiles to a image
    • when tif is used, the result will be a geotif

A sample mbtiles Database has been included, which some of the samples use

• due to size limitations, other mbtiles files cannot be included in this project
  • where used in the sample sripts, a link has been supplided where this file can be downloaded:
    • [http://www.mj10777.de/public/download/mbtiles/]

The Landez project also supports other functions, not yet tested:

• Blend tiles together
• Merge multiple sources of tiles (URL, WMS, MBTiles, Mapnik stylesheet) together.
• Composite a WMS layer with OpenStreetMap using transparency
• Add post-processing filters
• Replace a specific color by transparent pixels

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2014-02-28

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