Skip to contents

Create an HTML file that displays a tile preview using Leaflet.


tile_viewer(tiles, zoom, width = NULL, height = NULL, georef = TRUE, ...)



character, directory where tiles are stored.


character, zoom levels full range. Example format: "3-7".


NULL (default) for geospatial map tiles. The original image width in pixels for non-geographic, simple CRS tiles.


NULL (default) for geospatial map tiles. The original image height in pixels for non-geographic, simple CRS tiles.


logical, for non-geographic tiles only. If viewer = TRUE, then the Leaflet widget in preview.html will add map markers with coordinate labels on mouse click to assist with georeferencing of non-geographic tiles.


additional optional arguments include lng and lat for setting the view longitude and latitude. These three arguments only apply to geographic tiles. Viewer centering is (0, 0) by default.


nothing is returned, but a file is written to disk.


This function creates a file preview.html adjacent to the tiles base directory. When loaded in the browser, this file displays map tiles from the adjacent folder. For example, if tiles are stored in project/tiles, this function creates project/preview.html.

By default, tile() creates this file. The only reasons to call tile_viewer() directly after producing map tiles are: (1) if viewer = FALSE was set in the call to tile(), (2) if tile() was called multiple times, e.g., for different batches of zoom levels, and thus the most recent call did not use the full zoom range, or (3) preview.html was deleted for some other reason.

If calling this function directly, ensure that the min and max zoom, and original image pixel dimensions if applicable, match the generated tiles. These arguments are passed to tile_viewer} automatically when called within tile(), based on the source file provided to tile()`.

See also


tile_viewer(file.path(tempdir(), "tiles"), "3-7") # requires existing tiles