Thursday, January 18, 2007

Viewing Web Mapping Service Imagery

I didn't write this or think this idea up, but I wanted to share this terrific resource available through Google Earth. Rather than be real 'bloggie' and make the reader click all over the web to find out how to view web mapping service data, I'll copy and paste the highlights for you here. This is sure to create hours of fun.

Pulled directly from Using Google Earth blog: "Using a web mapping service (WMS), you can view alternate images in Google Earth. These appear as image overlays. This lesser known feature set allows you to display this information from any publicly available WMS. Available information from a WMS can include weather, geological features, seismic hazards, population depictions, time zones, forestry regions and much more.

Tip: Before you begin exploring WMS offerings in Google Earth, be sure to zoom in to the particular area on the globe that you want to explore. This improves performance and lessens the demand on the WMS servers that generously provide this free information."

To do this, follow these instructions copied from the Google Earth help web site:

You can place Web Mapping Service (WMS) image overlays in Google Earth. These are mapping images that are provided through a WMS over the Internet. They can show you interesting information, such as weather formations and conditions, topographical maps, alternate high resolution satellite imagery and more.

To place an WMS image overlay:

1. Position the 3D viewer in the location where you want to place the overlay image file.

Try to position the viewer so that it corresponds in viewing altitude to the overlay. If the overlay is of a detailed view, zoom into the subject area so that you don't have to make large adjustments later. By contrast, if the overlay covers a large area, make sure the entire area is encompassed in the 3D viewer with some margins for adjusting the imagery.

2. Select Image Overlay from the Add menu (or use other shortcut methods described in Creating A New Placemark). The New Image Overlay dialog box appears.

3. In the New dialog box, click the Refresh tab.

4. Click WMS Parameters. The Web Mapping Service Parameters dialog box appears.

5. Beside WMS Service, choose an appropriate service or click Add to use a URL (website address) for a WMS. After a brief period of time, Google Earth populates the Opaque and/or Transparent Layers fields with available layers from the WMS you choose.

6. Choose the appropriate layer(s) and click Add -> to add the layer(s) to the Selected Layers field. This places this information in the WMS image overlay you will see in Google Earth. To remove a layer from the Selected Layers field, select it and click <-Remove.

7. To set the order of selected layers as they appear in the 3D viewer, select the appropriate layers in the Selected Layers field and click Move Up or Move Down.

8. When you are finished, click OK

9. Provide a descriptive name in the Name field.

10. Click OK and the WMS layer that you selected will show up in your Places section.

Then there's more from Frank Taylor at Google Earth Blog

NOAA Releases Estuarine Bathymetric Data for Google Earth

"I was contacted recently by NOAA regarding their release of bathymetry data for estuaries around the US. These colorful datasets "...are an interpolated data set representing the most up-to-date depth sounding information that was available at the time of publication (1998)." Read more about the data. You can view the page providing access to the GE files here, where you select a region and then select which estuary you want to view. Then look for a link to "Google Earth Visualization files". Here's a sample of the Pamlico Sound in North Carolina. Thanks NOAA!"

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