Go to ArcGIS Home

View Now > Create Web Map

You should now be looking at

Read the four steps described in the left hand panel.

We will be doing two operations : choosing a base map and adding layers.

For our base map, let's just use what we currently see. It is a combination topographic and political map. What visual/information features make it so?

Next we will add a layer for natural hazards. Click the add a layer button and type hazards into the search box. Then add the USGS natural hazards layer. But before you do, click on the "Item Details" link. This information is called metadata. Take note of the different categories of information here.

Click "Done Adding Layers" at the bottom of the panel.

Hover over the middle of the three icons above the left-hand panel — "Show Contents of Map" — and click.

What you see is the list of the layers that are in this map. They are stacked from the the bottom up.

Uncheck USGS Natural Hazards and notice what happens on the map. Recheck and click on the layer name. Note the list that appears. What do you take this to be? Try checking and unchecking different items (it may take a few moments for the effects so be patient).

Hover over "Floods" so that you get a right pointing triangle and can open a "context menu" — use it to "enable popups." After you have done this, move your mouse to some of the floods along the Mississippi.

Click on a flood and study the popup window. Make sure you can ascertain what each piece of information is.

Repeat the above for earthquakes. Point at one in Virginia (or any hazard) and click on "Zoom to" and then click on the cluster of earthquakes near Richmond.

Now let's add the layer for USGS earthquake faults.

Add the layer USA population density. What kind of a map is this? What are the little polygons? What patterns do you notice, just in the shape and size of these polygons as you move east to west? What about the color? Click the details icon and generate a legend so that you can interpret the map. What information is missing from this legend? Can you locate this information anywhere? Go back to map contents and the context menu that let's you see description.

What do you make of the divisions used to make this color coded map?

Let's study this map in detail. History. Things you see from the air. What America is like. Are cities obsolete?

Note that the population density map is "on top of" the earthquake layer. Let's change that. Go to map contents. Hover and click to get the context menu for the population layer and make it "move down" and then examine the result.

Play. Move population density down one more layer.

Play. Change the transparency of the population layer so that you see clearly the differences in density but you also see the topography. Can you think of a caption/description?

Play. Where else have there been earthquakes recently? How do they compare (in terms of magnitude and other things that might make them more or less newsworthy)?

Play. Zoom in on hurricane Irene. Scout around to see if there are other layers on the web (use the add layers) related to hurricanes.