1.4.1 Using the OneGeology Portal
1.4.1.1 Viewing existing (portal) map data
The OneGeology portal is found at: http://portal.onegeology.org/ and is accessible as either an English (the default) or French language service.
You will need to use Internet Explorer 6 and above, Firefox 2 and above or recent versions of Safari, Opera, and Chrome. You will need to enable JavaScript and allow pop-ups.
When you open the portal you get a map of the world (Blue Marble: Next Generation+Topo+Bathy (Terra/MODIS)), but no geology. To view any existing geology maps you need to click on the View Layers option [1], to open the OneGeology catalogue listing.
[2] Click on the + buttons to expand the levels. Select a map by clicking on the box to the left of the map you wish to view. A tick will appear.
[3] Select all the map layers you wish to view before closing the catalogue listing. The selected maps should then be visible.
You may navigate around the map using the GIS tools found in the top left hand side of the menu bar. The functions of these tools is as follows:
[4] Zoom in — click on this image and then click on the world background map to zoom in centred on the clicked location. Click and drag a rectangle to zoom to a specific area.
[5] Zoom out — click on this image and then click on the world background map to zoom out centred on the clicked location. Click and drag a rectangle to zoom out from a specific area.
[6] View full global extent — click this image to start again with a view of the full world background map.
[7] Pan by clicking and dragging the map to move — click this image and then click and drag on the map to move to a different area (north, west, etc)
[8] Return back to previous map view
[9] If you have gone back to a previous view, you may use this tool to go forward.
[10] Refresh the map view
[11] Use this tool to get more information about the active map layers (this is termed a GetFeatureInfo request). Select the tool and click the map to open up a new window with detailed information about the geology at that point. The information returned and format of the information varies from map to map and layer to layer dependant upon how much information the provider organization wishes to display and the capabilities of the service.
To view metadata about the map layers and to change the way the layers are displayed you need to:
[12] Click on ‘ Active layers properties’ menu option. This will open a list of all the map layers that you have selected to be viewed in the portal.
[13] Within this dialogue menu you can manage the individual layers in the following ways:-
[14] Show or hide the map layer.
[15] Move the map layer up (so it lies above other layers and may obscure them).
[16] Move the map layer down (so it lies beneath other layers and may be obscured by them).
[17] Zoom to the extent of the map layer to make that particular map layer fill the centre of the map browser.
[18] Delete the map layer from the view (you can add it back again later).
[19] Change the opacity of the map layer (use the slider rule to change the % value to make underlying maps visible) so that it is possible to see through a layer to underlying layers where they overlap
[20] Click on this arrow to get more information about a layer, for example:-
- The data owner
- The layer title
- The legend of the map layer
- Information about the layer data and other digital data services of the data provider
- TC211/ISO 19115:2003 or FGDC metadata for the layer
- The service URL (you can use this URL to view the OneGeology WMS layer in any WMS client as described in later sections).
This (above) information is harvested automatically by the portal client software from the GetCapabilities response document of the WMS.
KML (Keyhole Markup Language)
The KML writing service from the portal client (currently called 'Save WMS or KML context' as described in the help file) is due to be improved to KML version 2.2 in 2009 - basically currently many layers will work with this and a few won't. My advice to you is try it and see if it works for you.
- click the tool then KML (Google Earth option) to write a KML file to your disk and then those layers that you had displaying at that time in the OneGeology portal client 'active layers' should be transferred (but clicked off not shown until you turn each layer on explicitly - to prevent client startup hangups) to the kml file which you save on your local disk. Double clicking that will start Google Earth usually on your desktop and you will see OneGeology layers added (as WMS references).
KML is a file format used to display geographic data in an Earth browser such as Google Earth, Google Maps. It is an XML–based language schema for expressing geographic annotation and visualization on existing or future Web -based, two-dimensional maps and three-dimensional Earth browsers. KML was developed for use with Google Earth, which was originally named Keyhole Earth Viewer. It was created by Keyhole Inc, which was acquired by Google in 2004, but is now an internationally recognised standard by the Open Geospatial Consortium (OGC) in it's version 2.2 form.
Section last modified : 19 January 2010.
