init(urlTemplate:)
Creates and returns a tile overlay object using the specified tile-access template.
Declaration
init(urlTemplate URLTemplate: String?)Parameters
- URLTemplate:
A string that you can use to build a URL to access your tile images. The string you specify can point to a local file or to an image on a remote server. To facilitate retrieving multiple tiles using the string, use the placeholder values
{x},{y},{z}, and{scale}as stand-ins for the x and y tile indexes, the zoom level, and the resolution of the tile image. If this parameter isnil, you need to provide custom implementations for the tile-loading methods of this class.
Return Value
An initialized tile overlay object.
Discussion
The default tile overlay object uses the template string you specify to request tiles. This template string needs to incorporate the {x}, {y}, {z}, and {scale} placeholder strings to facilitate the creation of a URL for requesting the appropriate tile. For example, if you have a server that vends tiles when you provide a URL in the form of http://myserver/tile?x=0&y=0&z=0&scale=1.0, you specify a template string of http://myserver/tile?x={x}&y={y}&z={z}&scale={scale}. The tile overlay object substitutes actual index values for your template’s placeholders before requesting the tile.