tile_viewer: Create an HTML tile preview

In ropensci/tiler: Create Geographic and Non-Geographic Map Tiles

Create an HTML tile preview

Description

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

Usage

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

Arguments

tiles	character, directory where tiles are stored.
zoom	character, zoom levels full range. Example format: "3-7".
width	NULL (default) for geospatial map tiles. The original image width in pixels for non-geographic, simple CRS tiles.
height	NULL (default) for geospatial map tiles. The original image height in pixels for non-geographic, simple CRS tiles.
georef	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.

Details

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()'.

Value

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

See Also

view_tiles(), tile()

Examples

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

ropensci/tiler documentation built on Sept. 14, 2023, 3:05 a.m.