Using GPS Visualizer
How to use the amazing GPS Visualizer Network Link
An incredible educational tool, the GPS Visualizer provides you and your students quick access to a wide range of geographic, scientific and visual data by drawing from resources on the internet and customizing it instantly to your view.It is quite easy to use, so if you are comfortable with technology you don't need this tutorial. If, on the other hand, you are new to Google Earth or 'don't know computers very well', read on for tips and instructions.
The first thing to do is to download the GPS Visualizer KML file which you can find by clicking here. Be sure to read the instructions on the page.
The GPS Visualizer (GV) Network Link works by taking information from Google Earth, sending it to the GPS Visualizer website, which gathers map information from many different government and commercial websites and presents it back to you, the user, through a link to a custom image overlay file. An image overlay is a picture that is pasted on top of the Google Earth display.
When you first load the GV Network Link it will appear in the Places panel, filed in the Temporary Places folder.
You will have a better experience with the Link if you set Google Earth to open the web browser inside the main Google Earth window. This will keep you from having to switch back and forth between a web browser and Google Earth. You can set the web browser to open inside Google Earth by clicking on the Tools menu and pulling down to Options. In the Options window click on the preferences tab and uncheck 'Show web results in external browser' then click OK to activate the change.
Next, zoom in to the geographic area of interest. For most data types you will want to be zoomed in fairly close having an area 10 - 20 miles (10 - 30 KM) on your screen. Be sure to look straight down at the ground (no tilt!). Once you are zoomed in right click on the network link and pull down to 'Refresh' to see what types of image data are available.
The available map overlays will vary depending on where in the world you are viewing. The most detailed overlays are in North America and Europe thanks in large part to the U.S.G.S. database of imagery and maps. Some frequent types include infrared, road, topographic and low resolution (250m) imagery.
You will need to refresh the link every time you change your view. While all the maps are checked by default, in order to view the map overlay you must click on the text beside the name of the map data you want to view.
Once you click on the text it will activate the web browser and send the area data to the GV site. A 'please wait' screen will appear momentarily and then you will be presented with a custom web page for the area you are viewing. As you scroll down the page, you will see that you may click on a link which launches a seperate window containing the image that will be included in the overlay and a bit further down a link to the .kmz file which will load the image as an overlay into Google Earth.
(opens in new browser window)
(loads the image over earth)
When you click on the KMZ link be prepared for a little wait as the image data is sent to your computer. Some of the images are very large (over 1M) so the slower your connection, the longer the wait. When the image overlay is finally loaded you will notice a new overlay icon in your Temporary Places folder. Once the image has loaded you may tilt away to your hearts content.
You may check or uncheck the box beside the overlay to show or hide the data. While it is selected you may also use the transparency slider if you need to compare the underlying terrain with the image data.
One thing to understand is that the image created as the overlay is not scalable. In other words it will not become clearer as you zoom in to earth like Google Earth does. If you zoom out you will see how only the specific area you were looking at has been overlayed.
Zoomed too far:
You are not limited to only the data parameters submitted by the link. You may also choose to Create a KML Overlay which transports you to the GV site and pre-enters your view information in the web form, while allowing you to set custom parameters from there.
Personally I find the GPS Visualizer an amazing, incredibly valuable educational tool, which is why I donated to the cause. If you find it of value I hope you too help keep the site going!