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Write a Mapbox Vector Tile pyramid to an MBTiles file

Source: R/ddbs_mvt.R
ddbs_write_mbtiles.Rd

Generates a pyramid of Mapbox Vector Tiles (MVT) from a spatial dataset and stores them in an MBTiles file (a SQLite database). For each tile in the requested zoom range the geometries are clipped and re-projected into tile space (ST_AsMVTGeom) and encoded into a binary vector tile (ST_AsMVT).

Usage

ddbs_write_mbtiles(
  x,
  dsn,
  layer_name = "layer",
  zoom_levels = 0:6,
  extent = 4096L,
  buffer = 256L,
  conn = NULL,
  overwrite = FALSE,
  quiet = FALSE
)

Arguments

x

Input spatial data. Can be:

  • A duckspatial_df object (lazy spatial data frame via dbplyr)

  • An sf object

  • A tbl_lazy from dbplyr

  • A character string naming a table/view in conn

Data is returned from this object.

dsn

Path to the output .mbtiles file.

layer_name

Name of the vector tile layer. This is the value you pass as source_layer when adding the layer in a web map. Defaults to "layer".

zoom_levels

Integer vector of zoom levels to generate (e.g. 0:8). Defaults to 0:6.

extent

Integer tile extent (resolution). Defaults to 4096.

buffer

Integer tile buffer in pixels. Defaults to 256.

conn

A connection object to a DuckDB database. If NULL, the function runs on a temporary DuckDB database.

overwrite

Logical. Overwrite dsn if it already exists. Defaults to FALSE.

quiet

A logical value. If TRUE, suppresses any informational messages. Defaults to FALSE.

Value

The path to dsn, invisibly.

Details

The input is re-projected to web mercator (EPSG:3857), so x must have a CRS. All non-geometry columns are carried into the tiles as feature properties; columns whose type is not supported by the vector tile format are cast to DOUBLE (numeric types) or VARCHAR (everything else), and BLOB columns are dropped.

Writing the SQLite container relies on DuckDB's sqlite extension, which is installed and loaded automatically (an internet connection may be required the first time).

MBTiles can be served with a vector tile server, or converted to PMTiles (e.g. with the pmtiles convert CLI) for static hosting. The resulting tiles can then be displayed with the mapgl package, for example:


library(mapgl)
maplibre() |>
  add_pmtiles_source(id = "src", url = "https://example.com/argentina.pmtiles") |>
  add_fill_layer(id = "fill", source = "src", source_layer = "argentina")

Examples

if (FALSE) { # \dontrun{
library(duckspatial)

argentina_ddbs <- ddbs_open_dataset(
  system.file("spatial/argentina.geojson", package = "duckspatial")
)

ddbs_write_mbtiles(
  argentina_ddbs,
  dsn         = tempfile(fileext = ".mbtiles"),
  layer_name  = "argentina",
  zoom_levels = 0:6
)
} # }