Web Services Usage

Web Map Services

Web Map Service (WMS) is an Open GIS standard specification for interactive mapping based on requesting map imaging for a server over the internet. ArcMap is a WMS client and allows users to access these services over the internet and add them to their maps as layers.

York Region has four free WMS published (available) as follows:

WMS	Description	URL
Base Map	York Region Base Map WMS is an open-access web map service for the basic geographic information in York Region including lakes, rivers, municipal boundaries and roads.	http://ww1.yorkmaps.ca/ArcGIS/services/WMS/YorkRegion_BaseMap_WMS/MapServer/WMSServer?
Orthos	York Region Orthos WMS is an open-access web map service of orthophotographs collected for specific areas of interest in 1995 and the entire region in 1999, 2002, 2005, 2007 and 2009.	http://ww1.yorkmaps.ca/ArcGIS/services/WMS/YorkRegion_OrthoImages_WMS/MapServer/WMSServer?
Elevation	York Region Elevation WMS is an open access map service containing the DEM and shaded relief representation of regional elevation.	http://ww1.yorkmaps.ca/ArcGIS/services/WMS/YorkRegion_Elevation_WMS/MapServer/WMSServer?
Foresty	York Region Forestry WMS is an open-access web map service of the regionally owned forest tracts and the trails within the forests.	http://ww1.yorkmaps.ca/ArcGIS/services/WMS/YorkRegion_Forestry_WMS/MapServer/WMSServer?

Adding a WMS service into an ArcMap project

1. Open ArcMap and in the GIS Servers folder in the Add Data dialog, double-click on "Add WMS Server".

2. In the dialog that appears, enter the URL to the WMS service. The URL that you specify for a WMS service needs to be the

complete URL. All WMS URLs end with a "?" character.

Press OK, this will create a connection to the server on which the service is running.

3. To Add WMS service to ArcMap use Add Data dialog and click on GIS Servers.

4. Select desired WMS service and click Add button.

5. Double click on the WMS service name or click Add buton.

Coordinate systems

The layers in a WMS service support a limited set of coordinate systems, depending on how the services ahs been configured by its author.
When you add a WMS service to a map, the current coordinate system of your data frame may not be supported by one or more layers in the service. If this is the case, two things will happen:

You will get the standard warning message from ArcMap telling you that the data you are adding has a geographic coordinate system that differs from other data in the map or from the current map projection.
The layers in the WMS service that don't support your data frame's current coordinate system won't be drawn in the map, and these layers will be shown with disabled check boxes in the table of contents.

To correct this situation you can change the coordinate system of your data frame to one that is supported by the layers in the WMS service.
To do this, right- click the WMS service layer in the table of contents and choose the Change Coordinate System command. The dialog that appears allows you to change the coordinate system to one that is supported by the WMS service:

If your map contains more than one WMS service, you can check the first option in this dialog to choose a coordinate system that is supported by all the layers in all the WMS services in your map.

What can you see in the table of contents for WMS service?

When you first add a WMS service to ArcMap, its entry in the table of contents is collapsed to save space. Expand the WMS layer in the table of contents to see the individual layers it contains.

By default, when you add a WMS service to ArcMap, all the layers in that service are available for display in the map. You can use the Layers tab in the WMS Layer Properties dialog to configure which layers in the service will be included in its table of contents entry, and specify the order in which they will be drawn:

When you identify a feature in a WMS service, the results aren't displayed in a tabular grid. Instead, the results are displayed inside an Internet Explorer control embedded in the Identify Results window.

When you identify a WMS service layer, the default option, <Top-Most-Layer>, doesn't work as expected. It is recommend that you either <Visible Layers> option, which will identify features in any of the visible layers in the WMS service layer, or choose the specific layer you want to identify.