User:Kannix/tile-download-scheme

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given:

  • .mbtiles database, containing only tiles that cover navigable waterways (e.g. cemt.mbtiles)
  • grid of download areas (boundingboxes like tiles at zoom-level 7 look good, see https://kap.grade.de/inland-chart-ol2.html )

steps:

  • extract all z/x/y from .mbtiles for selected boundingbox (zoom-level 15 seems to be a good choice)
    • see inland.ods for SQL selects
    • eg. boundingbox=tile z=7 x=65 y=45
    • save result as 7_65_45.csv
  • calculate corridor of tile names around the extracted tile names
    • see csv-15.py_
    • result is saved as 15_optimized.csv
  • calculate list of tile names at zoom-level 14-7
    • see csv-14-7.py_
    • result is saved as [zoomlevel]_optimized.csv
  • download tiles