GeoMapApp: Instructions and Tutorial

You will use Geomapapp to create elevation profiles and locate the lowest and highest elevation points in each city. These steps should be repeated for both Guangzhou and New Orleans.

Directions for creating elevation profiles for target coastal cities: Guanzhou and New Orleans. Read these directions before beginning work.

1. Go to GeoMapApp. Download the software according to the directions for your computer. Remember that if you are using a Mac with OS X 10.8 (Mountain Lion) or 10.9 (Mavericks), you will need to follow the instructions given in the "Mac OS X 'Mountain Lion' version 10.8 Installation Walkthrough" link found on the GeoMapApp Help Pages.
2. You will also need to load Java on your computer if you do not already have it.
3. Open GeoMapApp and explore basemap layers (see "DataLayers" dropdown menu tab in toolbar) for examining the topography of the study sites. The goal is to be able to view the topography of an area as accurately as possible so this will require selecting a dataset that gives us a high resolution (denoted by a measurement such as 10 m, 30 m, 1 km. The smaller the unit measure (in this list, 10m), the higher the resolution will be and therefore the more detail you will see on the map displayed when you zoom in. A 1km resolution is not helpful for our purposes here.
4. From the "DataLayers" dropdown menu, go to "Bathymetry and Land Topography" → "Global Models". There are two basemap layers available here that will allow us to explore the topography of the chosen cities in detail:
   • Global Multi-Resolution Topography (GMRT). Use this for places outside the US, such as Guangzhou. Do not use this one for New Orleans as the flat topography does not display accurately in this dataset.
   • NASA-ASTER-USGS Elevation Model. USA is 10m resolution in this one. Use this to explore New Orleans only. New Orleans has such slight elevation changes this high resolution map is the most accurate.
5. You can open multiple data layers and check and uncheck the layers to view or hide them. (note that the layer manager box sometimes gets hidden beneath the map).
6. Locate the region of interest and zoom in by clicking the "+" on the toolbar and drawing a box around the city you are targeting. Repeat this process until you have the right scale for exploring the elevation. Basically you'll want a range similar to the view you used in Google Earth to see the entire city.
7. 

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   Above is a screen shot in which the NASA Elevation model layer is turned on (checked in Layer Manager) and we are zoomed in on New Orleans to an extent that allows us to see small elevation changes when mousing over the terrain (zoom = 2812). The elevation is shown in the bar above the map next to the toolbar icons. Credit: GeoMapApp
   
   
   

   Notes:

   • To zoom out, click the "-" icon and left click multiple times until you reach the desired scale.
   • In order to locate your target cities (Guangzhou and New Orleans), use Google Earth to find the general coordinates and then use these coordinates in GeoMapApp to zoom in.
     

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     This screen shot shows GeoMapApp zoomed to Mumbai, India with Google Earth inset also zoomed to Mumbai. The coordinates 72°E; 19°N are the target coordinates for Mumbai. Credit: GeoMapApp
     
     
8. Explore the tabs at the top of the screen.
   1. Go to the square grid icon. This opens the "Global Grids" box.
   2. 

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      This screen shot shows the Global Grids box open on Mumbai, India. Credit: GeoMapApp
      
      
   3. Click on the Distance/Profile tool (this looks sort of like two mountains with a frame around them).
   4. Draw a line on your map in the area of interest. This will produce an elevation profile of your area.
      

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      This screen shot shows an elevation profile example of Mumbai. You will need to do several, searching for lower and higher elevations, to create a more comprehensive picture of the elevation of this large city (refer back to the elevation information you obtained using Google Earth.) Credit: GeoMapApp
      
      
   5. Click on the contour tool found in Global Grids. Adjust the contour interval to 5m in order to show enough detail in topography.
   6. This will open contour lines on the map.
   7. Use the elevation data in the profiles you create together with the contour map to determine the lowest and highest elevation for the city you are investigating. This will be entered in the Module 1 Assessment .
      

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      This screen shot shows 5m contours in Mumbai. Credit: GeoMapApp
      
   8. Open the population density basemap for your area. The resolution on this map is pretty low, you'll probably want to zoom out to get a good idea of what it is showing.
   9. Note the relationship between population density and elevation for your general area. This will be entered in the Module 1 Assessment.

References

GeoMapApp

Introduction to GeoMapApp: Exploring Earth's Topography. Annotated Teacher Edition

• Record Your Findings (Online Version)