Proxy

The Proxy provider is the simplest option that simply forwards tile requests to another HTTP(s) endpoint. This provider can be used for mapping services that operate in tiles (ZXY, TMS, or WMTS) or against bounds (i.e. WMS). TMS inverts the y coordinate compared to ZXY and WMTS formats, which is handled by the InvertY parameter.

The following is the typical request flow when using a proxy provider:

Name should be "proxy"

Configuration options:

Parameter	Description	Type	Required	Default
url	A URL pointing to the tile server. Should contain placeholders surrounded by "{}" that are replaced on-the-fly	string	Yes	None
inverty	Changes Y tile numbering to be South-to-North instead of North-to-South. Only impacts Y/y placeholder	bool	No	false
srid	What projection bounds should be in. Can only be 4326 or 3857	uint	No	4326

Parameter

Description

Type

Required

Default

url

A URL pointing to the tile server. Should contain placeholders surrounded by "{}" that are replaced on-the-fly

string

Yes

None

inverty

Changes Y tile numbering to be South-to-North instead of North-to-South. Only impacts Y/y placeholder

bool

false

srid

What projection bounds should be in. Can only be 4326 or 3857

uint

4326

The following placeholders are available in the URL:

Placeholder Description

Placeholder	Description
x or X	The X tile coordinate from the incoming request
y or Y	The Y tile coordinate either from the incoming request or the "flipped" equivalent if the `invertY` parameter is specified.
z or Z	The Z tile coordinate from the incoming request (aka "zoom")
xmin	The "west" coordinate of the bounding box defined by the incoming tile coordinates. In the projection specified by `srid`.
xmax	The "east" coordinate of the bounding box defined by the incoming tile coordinates. In the projection specified by `srid`.
ymin	The "north" coordinate of the bounding box defined by the incoming tile coordinates. In the projection specified by `srid`. Not impacted by the `invertY` parameter.
ymax	The "south" coordinate of the bounding box defined by the incoming tile coordinates. In the projection specified by `srid`. Not impacted by the `invertY` parameter.
env.XXX	An environment variable whose name is XXX
ctx.XXX	A context variable (typically an HTTP header) whose name is XXX
layer.XXX	If the layer includes a pattern with a placeholder of XXX, this is the replacement value from the used layer name

x or X

The X tile coordinate from the incoming request

y or Y

The Y tile coordinate either from the incoming request or the "flipped" equivalent if the invertY parameter is specified.

z or Z

The Z tile coordinate from the incoming request (aka "zoom")

xmin

The "west" coordinate of the bounding box defined by the incoming tile coordinates. In the projection specified by srid.

xmax

The "east" coordinate of the bounding box defined by the incoming tile coordinates. In the projection specified by srid.

ymin

The "north" coordinate of the bounding box defined by the incoming tile coordinates. In the projection specified by srid. Not impacted by the invertY parameter.

ymax

The "south" coordinate of the bounding box defined by the incoming tile coordinates. In the projection specified by srid. Not impacted by the invertY parameter.

env.XXX

An environment variable whose name is XXX

ctx.XXX

A context variable (typically an HTTP header) whose name is XXX

layer.XXX

If the layer includes a pattern with a placeholder of XXX, this is the replacement value from the used layer name

Example:

provider:
  name: proxy
  url: https://tile.openstreetmap.org/{z}/{x}/{y}.png?key={env.key}&agent={ctx.User-Agent}