[jleedev]

A single ocean tile on mapbox is 39 bytes:

  1a25 7802 0a05 7761 7465 7228 8020 1217
  1803 2213 0980 69e0 7f1a dfa8 0100 00bf
  bf01 e0a8 0100 0f

Decodes to this protobuf:

  layers {                                                                                                                                                                                         
    name: "water"                                                                                                                                                                                  
    features {
      type: POLYGON
      geometry: 9
      geometry: 13440
      geometry: 16352
      geometry: 26
      geometry: 21599
      geometry: 0
      geometry: 0
      geometry: 24511
      geometry: 21600
      geometry: 0
      geometry: 15
    }
    extent: 4096
    version: 2
  }

Geometry interpretation is here: https://github.com/mapbox/vector-tile-spec/tree/master/2.1#4...

And produces this geometry before reprojecting to the tile coordinates:

  Layer name: water
  Geometry: Polygon
  Feature Count: 1
  Extent: (0.000000, 0.000000) - (4096.000000, 4096.000000)
  Layer SRS WKT:
  (unknown)
  mvt_id: Integer64 (0.0)
  OGRFeature(water):0
    POLYGON ((0 0,0 4096,4096 4096,4096 0,0 0))

But of course, this doesn't specify a color, just "the ocean is a rectangle".