Signal K•3w ago

OSM OpenCPN MBTiles are not rendered in Freeboard-SK

The MBTiles listed at https://wiki.openstreetmap.org/wiki/MBTiles are showing up on OpenCPN, but not in Freeboard. Maybe due to different schema compared to signalk-world-coastline-map? signalk-world-coastline-map is showing and has the following schema:

CREATE TABLE tiles (
            zoom_level integer,
            tile_column integer,
            tile_row integer,
            tile_data blob);
CREATE TABLE metadata
        (name text, value text);
CREATE TABLE grids (zoom_level integer, tile_column integer,
    tile_row integer, grid blob);
CREATE TABLE grid_data (zoom_level integer, tile_column
    integer, tile_row integer, key_name text, key_json text);
CREATE TABLE sqlite_stat1(tbl,idx,stat);
CREATE UNIQUE INDEX name on metadata (name);
CREATE UNIQUE INDEX tile_index on tiles
        (zoom_level, tile_column, tile_row);

CREATE TABLE tiles (
            zoom_level integer,
            tile_column integer,
            tile_row integer,
            tile_data blob);
CREATE TABLE metadata
        (name text, value text);
CREATE TABLE grids (zoom_level integer, tile_column integer,
    tile_row integer, grid blob);
CREATE TABLE grid_data (zoom_level integer, tile_column
    integer, tile_row integer, key_name text, key_json text);
CREATE TABLE sqlite_stat1(tbl,idx,stat);
CREATE UNIQUE INDEX name on metadata (name);
CREATE UNIQUE INDEX tile_index on tiles
        (zoom_level, tile_column, tile_row);

https://ftp.gwdg.de/pub/misc/openstreetmap/openseamap/charts/mbtiles/OSM-OpenCPN2-Adria.mbtiles is not showing and has a different schema:

CREATE TABLE metadata (name text, value text);
CREATE TABLE tiles (zoom_level integer, tile_column integer, tile_row integer, tile_data blob);
CREATE UNIQUE INDEX tile_index on tiles (zoom_level, tile_column, tile_row);

CREATE TABLE metadata (name text, value text);
CREATE TABLE tiles (zoom_level integer, tile_column integer, tile_row integer, tile_data blob);
CREATE UNIQUE INDEX tile_index on tiles (zoom_level, tile_column, tile_row);

5 Replies

AdrianP•3w ago

So Freeboard-SK uses the type and format attributes in the meta data at /signalk/v2/api/resources/chart/{chart-id} to determine the type of chart source. For a raster MBTiles chart source it should look something like this....

"mbtiles_01": {
    "identifier": "mbtiles_01",
    "name": "MBTILES_01",
    "description": "my mbtiles chart",
    "bounds": [-202.5, 56.1700229829, -112.5, 75.4971573189],
    "minzoom": 3,
    "maxzoom": 19,
    "format": "png",
    "type": "tilelayer",
    "scale": 250000,
    "url": "/signalk/chart-tiles/mbtiles_01/{z}/{x}/{y}",
    "layers": []
  }

"mbtiles_01": {
    "identifier": "mbtiles_01",
    "name": "MBTILES_01",
    "description": "my mbtiles chart",
    "bounds": [-202.5, 56.1700229829, -112.5, 75.4971573189],
    "minzoom": 3,
    "maxzoom": 19,
    "format": "png",
    "type": "tilelayer",
    "scale": 250000,
    "url": "/signalk/chart-tiles/mbtiles_01/{z}/{x}/{y}",
    "layers": []
  }

What does the meta data for the chart that doesn't work look like?

TikaOP•3w ago

It's

  "OSM-OpenCPN2-Adria": {
    "identifier": "OSM-OpenCPN2-Adria",
    "name": "Adria",
    "bounds": [
      11.25,
      36.59788913307021,
      22.5,
      47.04018214480666
    ],
    "minzoom": 10,
    "maxzoom": 18,
    "format": "png",
    "type": "tilelayer",
    "scale": 250000,
    "url": "/signalk/chart-tiles/OSM-OpenCPN2-Adria/{z}/{x}/{y}",
    "layers": []
  },

  "OSM-OpenCPN2-Adria": {
    "identifier": "OSM-OpenCPN2-Adria",
    "name": "Adria",
    "bounds": [
      11.25,
      36.59788913307021,
      22.5,
      47.04018214480666
    ],
    "minzoom": 10,
    "maxzoom": 18,
    "format": "png",
    "type": "tilelayer",
    "scale": 250000,
    "url": "/signalk/chart-tiles/OSM-OpenCPN2-Adria/{z}/{x}/{y}",
    "layers": []
  },

AdrianP•3w ago

OK so it appears that Openlayers has issues with the response to tile requests. Out of curiosity if you enter the path to a tile in the browser (e.g. /signalk/chart-tiles/OSM-OpenCPN2-Adria/5/2/8) is the tile image displayed?

TikaOP•3w ago

/signalk/chart-tiles/OSM-OpenCPN2-Adria/11/12/40 yields "Not Found" /signalk/chart-tiles/world-coastline/7/30/30 shows an image

AdrianP•3w ago

So the chart plugin is not returning an image for the request..... the charts-plugin uses the @mapbox/mbtiles library to process MBTiles so it looks like the difference in schema may not be supported by the library.

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OSM OpenCPN MBTiles are not rendered in Freeboard-SK

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