A Web Map Service (WMS) is a standard protocol for serving georeferenced map images over the Internet. The images are generated by a map server using data from a GIS database. (taken from the Wikipedia Article.)
WMS requires a georeferenced map. Choose the Scale and Coordinate System command from the Map menu to set the map scale and a coordinate system. Real world coordinates do not have to be necessarily defined. They can be left at (0/0) for example.
To set up a map from a WMS server choose the WMS - Web Map Service command from the Background Map menu. The WMS - Web Map Service dialog appears.
The WMS servers are listed in the upper box of the WMS - Web Map Service dialog.
Add a WMS Server
- Click the Add button.
- The Add WMS Server dialog appears.
- Enter the Name of the server, the URL, the Version and, if required, a Login with Password, the Token Server URL and a Key.
- Click the OK button when finished.
- The WMS server appears in the WMS server box.
Connect to a WMS Server
Select a WMS server from the list and click Connect. If the connection was successful, OCAD gets a list from the server with the available layers. These layers are listed in the WMS layer table of the WMS - Web Map Service dialog. Read the WMS Layer article to learn how to use layers as Background Maps.
Edit WMS Server Properties
Select a WMS server and click the Edit button to edit its properties. The Edit WMS Server Properties dialog appears which is equal to the Add WMS Server dialog.
Remove a WMS Server
Click the Remove button to remove the selected WMS server from the list.
After connecting to a WMS server the available WMS layers are listed in the WMS layer box.
- Select a WMS layer in the list and choose an Image format from dropdown list (those formats are provided by the WMS server).
- Choose an option how to add the selected layers:
- Add Selected Layers as WMS Layers to Background Maps (Online)
- This is an online Background Map . It is updated by the WMS Server by each change of the map view. This can take a moment. Choose the online option only if you are using a fast WMS server and work woth high speed internet connection. As an alternative, you can add the layer as an offline background map.
- Add current view of selected layers to background maps (Offline)
- Add User Defined Extent of Selected Layers to Background Maps (Offline)
- Define the Offline folder. The current map folder is set as default.
- Define the Resolution.
- Define the Extent (minimum easting, maximum easting, minimum northing, maximum northing). The current view extent is set as a default when opening the WMS dialog but the entries are not updated automatically by changing the view. The extent can be updated by clicking the Set extent to current view button.
- With this offline option an image of the chosen WMS layer of the defined extent is downloaded from the WMS server and added as a custom background map to the map. It does not get updated when changing the view.
- Click the Add button.
Web Map Services generally provide their images in multiple spatial reference systems. OCAD can only access to WMS if the OCAD maps' coordinate system (ex. Swiss Grid CH1903) is supported by the WMS. Then the Spatial reference system is automatically set to the corresponding EPSG code. If the chosen coordinate system is not compatible with the WMS, the Spatial reference system caption in the WMS dialog remains empty.
Click the Close button when finished.
Manage the view or remove the WMS maps by choosing the Manage command from the Background Map menu:
Back to the Background Map page.