The OGC is a body which has developed standards to support interoperability between web mapping applications such as OHEB’s MAPSTER and Google Earth (GE). MAPSTER uses several OGC compliant Web Mapping Services (WMS) to support the sharing of OHEB spatial data on the Internet. OHEB WMS’s are organized by ‘theme’ to provide a more intuitive understanding of the content of each WMS (see URL's in step 3). At version 4, GE has added support for OGC WMS, facilitating the integration of OHEB and GE spatial data layers in the GE application. Please follow the instructions below to add OHEB WMS’s to GE.
1. Install Google Earth 4 (September 2006 release or later)
Access and install GE version 4 at: http://earth.google.com/download-earth.html
2. Create Image Overlay
Once installed, Start GE > go to the ‘Add’ menu > select ‘Image Overlay’
In the Image Overlay popup box:
Enter a Name for the new ‘Overlay’ you will be adding to GE
Set the ‘Transparency’ slider control to at least half way between ‘clear’ and ‘opaque’. (Tip: setting closer to opaque will help you view the layers when they are initially displayed.)
Select the ‘Refresh’ tab, and mouse click on the ‘WMS parameters’ button. The ‘Web Mapping Service Parameters’ popup box will display
3. Set Web Mapping Service Parameters
In the ‘Web Mapping Service Parameters’ popup box:
Mouse click on the ‘Add’ button adjacent the ‘WMS Server’ field at the top of the popup box.
The ‘Enter WMS Server URL’ popup box will display:
To add an OHEB WMS to GE:
Copy and paste one of the URL's below into the ‘Enter WMS Server URL’ box
In the example below, the HEBInland WMS URL has been pasted into the popup box.
Once you have copied and pasted a URL into the box, press OK
4. Select the Spatial Layers
A connection will automatically be made to the OHEB WMS and a list of spatial data layers from that service will be displayed in the left window pane of the ‘Web Mapping Service Parameters’ popup box
Select the layers you want to display in GE by highlighting them (single mouse click) in the left window pane, and then mouse click on the ‘Add’ button adjacent the layer list to add them to the “Selected layers’ list.
When finished adding layers, press OK
Then press OK again in the ‘Image Overlay’ box to load the layers into GE
Notes:
GE may require several seconds to produce the initial display of the GE imagery and the OHEB WMS layers. When zooming in / out or panning in GE, also allow several seconds for a clear display to be rendered.
Additional OHEB WMS’s may be added to GE by following the same process as described above. Published OGC WMS’s from other sources may also be added using these instructions.
5. Your new Google Earth listing
As well as the spatial layers being displayed on the GE map, a new listing for the OHEB WMS will be added to the left side bar under ‘Places’. This listing will have the same name which you assigned in Step 2.
More Miscellaneous Notes:
Loading too many layers from a WMS into GE may cause overload problems and impact GE performance
Some layers do not appear to display when loaded into the GE application
Some layers may be difficult to see due to the colour used to render the layer
Control of feature symbology is only available with GE Pro ($400.00)
