WMS (Web Map Service) is a standard protocol for serving georeferenced map images over the Internet that are generated by map servers using data from GIS databases. These maps or map data layers are mostly provided by government organizations or education institutions.
WMS can serve almost any type of map. Beginning with topographic maps, historic maps, satellite, and aerial images, cycling routes, town plans, ending with various data layers like cadastral maps, weather services, environmental layers, etc.
For more info, read this Wiki page. WMS maps are managed in the WMS tab of Locus map manager.
Locus Map offers a library of worldwide WMS sources where you can select or you can enter a direct URL to add any WMS source you wish to the app.
Other Action menu items:
After a WMS map is activated two new control buttons appear in the upper left corner:
Current WMS support does not have any mechanism for tile caching. All data are stored only in your device's temporary memory.