Part 1: Explore a Visualization of the Seafloor

1. Open the GeoMapApp homepage in a new window.
• Click the link for your computer's operating system.
• Scroll to the bottom of the page and read the terms of distribution and click AGREE to download the software.
2. When the download is complete, locate the program file on your computer (wherever your downloads are stored) and double-click the GeoMapApp icon to start the program.
   • Click OK to open the default Mercator Base Map.
   Show me
   Hide
   
   • You'll have an opportunity to create a directory or folder to store preferences for the program. Click Cancel to skip this step for your initial exploration.
3. Once GeoMapApp is running, you'll see a map image of Earth.
   Show me how it should look
   Hide

   

When we look at world maps, we usually focus on the continents. Try to reverse your thinking and look at the ocean floor as the main feature of this map. As you visually explore the map, you may notice something quite odd...

- Think about what you see: What do you think the different colors represent on this map? Do you have any ideas for how the map might have been made? Why do you think some continents appear twice?

Zooming in and out

To zoom in on the map, click the magnifying glass with a plus sign in the toolbar then click on the location you want to enlarge. Use the magnifying glass with the minus sign to zoom out.

Reading the cursor location

Move your cursor across the map image and notice the changing values at the top of the map. These values show your cursor's location as a set of latitude and longitude coordinates. The longitude value (E or W) tells how far east or west of the prime meridian the location is. The latitude value (N or S) tells how far north or south of the equator the location is.

Displaying a distance scale

Access the Overlays drop-down menu and select Distance Scale to turn on a distance scale.