In this lesson, you'll open a web map and learn how to navigate and work with it using map tools as you explore volcanoes and the risk of lava flow on the island of Hawaii.
Open the map
You'll start by opening a map of lava flow hazard zones on the island of Hawaii.
- Go to the ArcGIS Online group Get Started with Map Viewer.
A group is a collection of content on ArcGIS Online. This group contains the data for these lessons.
- Click the thumbnail of the Hawaii Island Lava Flow Risk map by Learn_ArcGIS to open it.
The map opens to show the island of Hawaii. Instead of beaches and greenery, you see a geologic classification of the island into lava flow hazard zones of different severity. The map also shows volcanoes, emergency shelters, and highways.
Explore the map
The map contains layers, and layers contain features. For example, each volcano is a feature in the Volcanoes layer. In this section, you'll get information about features and navigate the map.
- Click a volcano on the map, such as Mauna Loa.
Mauna Loa, which last erupted in 1984, is one of three active volcanoes on the island. (Mauna Kea is extinct.)
- Click the thumbnail image on the pop-up.
A large, captioned version of the image opens in a new browser tab or window.
- Close the tab or window with the detailed image.
- At the bottom of the pop-up, click Zoom to.
The map zooms in on the feature and you can see the terrain.
- Close the pop-up by clicking the X in its title bar.
- Click the Default extent button in the upper left corner of the map.
- Click a lava flow hazard zone.
Another pop-up opens with information about the feature and a thumbnail image that links to a larger picture.
- Click the thumbnail image on the pop-up to see the large, captioned image.
- Close the browser tab with the detailed image and close the pop-up on the map.
- On your own, learn more about the volcanoes, hazard zones, and emergency shelters. Use the map navigation tools or your mouse wheel to zoom in and out.
Press the Shift key and draw a box on the map to zoom in on a particular area.
- When you're finished, click the Default extent button to return to a full view of the island.
Now that you know something about how the map works, you'll look at how it's put together.
View the map contents
To work directly with the map layers, you need to switch to the Contents view of the map.
- At the top of the Details pane on the left, click the Content button.
The order of layers on the Contents pane is the order in which they are drawn on the map. At the bottom, every map has a basemap layer that covers the entire world. Every layer, except the basemap, can be turned on or off.
- On the Contents pane, check the box next to the Lava Flow Hazard Zones layer to turn the layer off.
You see the Terrain layer underneath. (The Terrain layer was already partially visible because of a transparency setting on the Lava Flow Hazard Zones layer.)
- Turn off the Terrain layer to see the Topographic basemap.
- Turn both layers back on.
You can adjust the transparency of any layer.
- In the Contents pane, point to the Lava Flow Hazard Zones layer. Click the More Options button and choose Transparency.
The layer is approximately 40 percent transparent.
- Move the Transparency slider back and forth.
When the layer is completely opaque, the terrain is obscured. At the other extreme, the Lava Flow Hazard Zones layer is invisible.
- Move the Transparency slider to a position you like. Move the mouse pointer over some white space on the Contents pane, and click if necessary, to close the layer properties.
Now that you've explored the map, you'll assemble it in the next lesson.
Use map tools
You can also work with the map using tools on the ribbon.
- On the ribbon, click the Measure button and click the Distance tool.
- On the map, click Mauna Loa to start a measurement.
- Move the mouse pointer to another volcano, such as Hualalai, and double-click to end the measurement.
- Make a few more measurements. When you're finished, close the Find area, length, or location box.
During a measurement, click once to change the direction of the line.
- On the ribbon, click the Basemap button to open the Basemap Gallery. Click Oceans or another basemap.
The new basemap is shown.
- Change the basemap back to the Topographic basemap.
In this lesson, you explored a map that somebody else had already made and became familiar with its layers and data. In the next lesson, you'll use similar data to create your own map of Hawaii and its lava flow zones.