Part 1—Download and Install Software and Data

Step 1–Download and Launch GeoMapApp Software

  1. Open the GeoMapApp home page in a new window.

    • From the Download Links panel on the left of the page, click the link for your computer's operating system.
    • On the new Web page that comes up for your computer, scroll to the bottom of the page, read the terms of distribution, and click AGREE to download the software.
    • Mac Users Note: GeoMapApp may not easily download and launch on your computer. Follow the trouble shooting instructions, located here if this is the case.
  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. When GeoMapApp launches, three maps are displayed. Click on the center map and Agree to select the default Base Map in South Polar projection.
  3. Once GeoMapApp is running, the base map is displayed.
  4. If you prefer, you can launch GeoMapApp directly from the Internet using Java Web Start. To do this, click the "here" link located mid-way down the GeoMapApp home page instead of the Download Links. Click the question mark icon on the page if you need help using Java Web Start.
  5. Once the program has loaded, take a few minutes to explore the built-in tools and the base map.

Step 2–Explore the GeoMapApp Tool Bar

  1. Take a few minutes now to review the map projection you have loaded. Notice that the South Pole is in the center of the map. To the upper left is South America and the southern Atlantic. In the lower right you will find Australia. It can be easy to confuse directions with this map projection. For example, both the top and the bottom of the map are north! As you work with this projection keep the big picture in mind and consider direction carefully.
  2. Click the Zoom tool (magnifying glass icon) at the upper left of the tool bar. When this tool is selected you will be able to zoom to any area of interest by moving the mouse over a location and clicking. Go ahead and zoom in to the Ross Sea. (3 clicks should be enough)
  3. You may have noticed that Antarctica looks a bit different than you have seen on other maps. Since much of the continent is covered in ice, the actual coastline is not always visible. From the menu at the top of the GeoMapApp window choose Overlays. From the dropdown menu that appears, select Coastlines > Antarctic Coastline (low resolution-fast).

  4. You should now be able to see Antarctica's coastline on your map. Technically, not all the coastline depicted is actually as we might imagine. The line moving from south to north along the edge of the Ross Sea is actually the grounding line of the West Antarctic Ice Sheet. Although the WAIS covers most of the southern Ross Sea, the grounding line is the transition from the floating ice shelf to the ice sheet sitting on bedrock. In this investigation you will be looking for Ross Sea floor evidence of changes in location of the grounding line.
    5. You probably also noticed that a window called Layer Manager appears as you access parts of the toolbar and menu. Essentially this is a list of what overlays you are placing on your map window. You can change the transparency of the layer by moving the slider and change the order of the layers by clicking the up/down arrows on the right. You can also use your mouse to drag the layer manager to the side as you work or minimize it by clicking the yellow icon. While you work, you should not close the layer manager (red icon) as this will remove the layers from the map window.
  5. Select the Distance / Profile tool. It is the sixth icon from the left under the menu and looks like an inverted "V" on a grid. This tool will bring up a higher resolution set of elevation data and enable you to make graphical profiles of elevation. After selecting the tool, it may take a few seconds to load. Again, notice that a new layer appears on your layer manager.
    6. Once the layer has loaded you will also see a Global Grids window open. Take a few moments to review this window before proceeding. For example, notice that the histogram shows the elevations represented by different colors on the map window.
  6. You may have wondered what happened to the grounding line layer. Remember you will need to move it higher on the Layer Manager list to place it over the new elevation data. Click the up arrow to the right of the Antarctic Coastline layer to position it on top of the GMRT layer.
  7. Next you will create a profile running perpendicular to the grounding line that runs along the W150 longitude. To do this simply click and drag across the line while the Distance / Profile tool is selected. Once you release the mouse at the end of the transect a graphical profile of elevation along your transect will appear. (Remember, as with all pop-up windows, you can move the profile to a convenient spot on your desktop.) Move your mouse cursor along the graph. Notice that the location on the graph is correlated to the location on the map window by a small icon that moves along your transect?

    Consider the following questions while viewing the profile graph:
    • What is the elevation of the grounding line where the transect crosses? (hint: you can read this at the top of the profile window or off of the graph.)
    • What are the longitude and latitude coordinates of the start of your transect?
    • What is the vertical exaggeration of the profile?
    • Why do you think this exaggeration is done? (Hint: think back to the sonar articles.)
    8. You can save profiles you create to folders on your desktop by selecting "Save" from the Profile menu. You will need to save profiles and map images in Parts 2 and 3 as you design and complete your investigation.
  8. For now, close the profile by clicking the red button on the Profile window.

Step 3–View the current configuration of the Ross Ice Shelf and the WAIS grounding line

Before you begin, reload the the South Polar projection base map, add the Antarctic Coastline layer and position it on top of the GMRT layer.
  1. From the dropdown menus at the top of the screen, select Overlays > Antarctic Ice Shelf Edge. You should now be able to see the outer edge of the ice shelf extending into the Ross Sea. (Remember: The ice shelf is floating ice. The grounding line demarks the transition from floating ice to the portion of the West Antarctic Ice Sheet that is sitting on bedrock.)


    • What is the approximate latitude of the ice shelf edge?
    2. Keep in mind that the entire ice sheet is dynamic and in constant motion. Recent research has revealed that the northward flow of the ice is not, however, uniform. In fact, several high velocity ice streams are responsible for the bulk of ice delivery from the continent to the ice shelves. Along with ice volume, these ice streams deliver glacial sediments to the continental shelf.
  2. To view ice velocity data select Basemap from the GeoMapApp menu. From the dropdown menus select Regional grids > Ice Sheet > Ice Flow Velocities (Rignot et al. 2011)


  3. As with the Profile tool, you will notice a window open with a color key histogram to help you interpret the map.
    Use the map and window to answer the following questions:
  4. When you select this layer the zoom will move back out to full extent automatically. You will need to zoom back in on the Ross Sea as before. Now, move the ice shelf edge and coastline layers back to the top of the Layer Manager and save a map image for your report.
    • To save map images select File > Save Map Window as Image/Grid File. You will be prompted to choose the file extension that you prefer and destination folder. Make sure to give your file a name that will allow you to find it later.
    The image should include: Antarctic coastline, ice shelf edge, and illustration of ice stream velocities.
    As you write your research report in Part 3, you can use this completed graphic and map image to illustrate the current configuration of the West Antarctic Ice Sheet draining into the Ross Sea.
    5. You should now know how to move around and use the basic tools in GeoMapApp. If possible, keep the GeoMapApp window open and the layers loaded as you begin Part 2.