From 30b919196b72351c43a5834b66a36068c0588fe0 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Minh=20Nguye=CC=82=CC=83n?= Date: Tue, 9 May 2017 18:36:20 -0700 Subject: [ios, macos] Factored out tile URL template guide MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Factored out redundant tile URL template documentation from the MGLRasterSource and MGLVectorSource documentation into a jazzy guide. This documentation used to live in one place, on a method on MGLTileSource, but that method had to be moved to MGLTileSource’s concrete subclasses. A jazzy guide is easier to link to, in any case. --- platform/macos/docs/guides/Tile URL Templates.md | 98 ++++++++++++++++++++++++ 1 file changed, 98 insertions(+) create mode 100644 platform/macos/docs/guides/Tile URL Templates.md (limited to 'platform/macos/docs') diff --git a/platform/macos/docs/guides/Tile URL Templates.md b/platform/macos/docs/guides/Tile URL Templates.md new file mode 100644 index 0000000000..01672c6686 --- /dev/null +++ b/platform/macos/docs/guides/Tile URL Templates.md @@ -0,0 +1,98 @@ + +# Tile URL Templates + +`MGLTileSource` objects, specifically `MGLRasterSource` and `MGLVectorSource` +objects, can be created using an initializer that accepts an array of tile URL +templates. Tile URL templates are strings that specify the URLs of the vector +tiles or raster tile images to load. A template resembles an absolute URL, but +with any number of placeholder strings that the source evaluates based on the +tile it needs to load. For example: + +* `http://www.example.com/tiles/{z}/{x}/{y}.pbf` could be + evaluated as `http://www.example.com/tiles/14/6/9.pbf`. +* `http://www.example.com/tiles/{z}/{x}/{y}{ratio}.png` could be + evaluated as `http://www.example.com/tiles/14/6/9@2x.png`. + +Tile URL templates are also used to define tilesets in TileJSON manifests or +[`raster`](https://www.mapbox.com/mapbox-gl-js/style-spec/#sources-raster-tiles) +and +[`vector`](https://www.mapbox.com/mapbox-gl-js/style-spec/#sources-vector-tiles) +sources in style JSON files. See the +[TileJSON specification](https://github.com/mapbox/tilejson-spec/tree/master/2.2.0) +for information about tile URL templates in the context of a TileJSON or style +JSON file. + +Tile sources support the following placeholder strings in tile URL templates, +all of which are optional: + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
Placeholder stringDescription
{x}The index of the tile along the map’s x axis according to Spherical + Mercator projection. If the value is 0, the tile’s left edge corresponds + to the 180th meridian west. If the value is 2z−1, + the tile’s right edge corresponds to the 180th meridian east.
{y}The index of the tile along the map’s y axis according to Spherical + Mercator projection. If the value is 0, the tile’s tile edge corresponds + to arctan(sinh(π)), or approximately 85.0511 degrees north. If the value + is 2z−1, the tile’s bottom edge corresponds to + −arctan(sinh(π)), or approximately 85.0511 degrees south. The y axis is + inverted if the options parameter contains + MGLTileSourceOptionTileCoordinateSystem with a value of + MGLTileCoordinateSystemTMS.
{z}The tile’s zoom level. At zoom level 0, each tile covers the entire + world map; at zoom level 1, it covers ¼ of the world; at zoom level 2, + 1⁄16 of the world, and so on. For tiles loaded by + a MGLRasterSource object, whether the tile zoom level + matches the map’s current zoom level depends on the value of the + source’s tile size as specified in the + MGLTileSourceOptionTileSize key of the options + parameter.
{bbox-epsg-3857}The tile’s bounding box, expressed as a comma-separated list of the + tile’s western, southern, eastern, and northern extents according to + Spherical Mercator (EPSG:3857) projection. The bounding box is typically + used with map services conforming to the + Web Map Service + protocol.
{quadkey}A quadkey indicating both the tile’s location and its zoom level. The + quadkey is typically used with + Bing Maps. +
{ratio}A suffix indicating the resolution of the tile image. The suffix is the + empty string for standard resolution displays and @2x for + Retina displays. +
{prefix}Two hexadecimal digits chosen such that each visible tile has a + different prefix. The prefix is typically used for domain sharding.
+ +For more information about the `{x}`, `{y}`, and `{z}` placeholder strings, +consult the +[OpenStreetMap Wiki](https://wiki.openstreetmap.org/wiki/Slippy_map_tilenames). -- cgit v1.2.1