Web Map Service (WMS)
The Standard Web Map Service (WMS) provides a simple HTTP interface to request map images from one or more distributed servers on the Internet. A WMS request defines which geographic layers and area of interest to process. The response to the request is one or more map images (in JPEG, PNG, ... format) that can be displayed on an Internet browser. The Standard also supports the ability to specify whether the returned image should be transparent, so that you can combine layers from different servers.
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