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Get started

Welcome to Explorer! To get started with the app, you'll open a 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.


If you've completed the Get Started with ArcGIS Online Learn lesson, this will seem familiar. You are doing many of the same things you did in Explore a map but using Explorer instead of a browser. Return to that lesson to learn how to create the map.

Install and open Explorer

Install Explorer from the App Store if you don't already have it on your device. Start the app. You can sign in to your ArcGIS account or use the app without signing in.


If you don't have an ArcGIS account, you can sign up for a free trial or create an account.

Without signing in, you can view sample maps and search for public maps on ArcGIS Online.

If you've never opened a map in the app, you'll see the Maps browse screen where you explore and find maps. If you were already signed in and you have previously opened a map in the app, you'll see your previous map. If it isn't the Hawaii Island Lava Flow map you'll use here, select Maps to go to the Maps browse screen.

Find and open the map

You'll use the Hawaii Island Lava Flow map to become familiar with Explorer. If you are not signed in, you'll see this map in the Explorer Maps category. Otherwise, search for it in the Maps browse screen. Select the Hawaii Island Lava Flow map to open it.

Hawaii Island Lava Flow map

You're looking for the Hawaii Island Lava Flow map by Learn ArcGIS. You can use Overflow Overflow to see map details and confirm if you found the right map before opening 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 the features and navigate the map.

  1. Select a volcano on the map, such as Mauna Loa.
    List of features

    Selecting it shows all the features at its location. For Mauna Loa, there is the volcano itself and one or more lava flow hazard zones.

  2. From the list of features, select the volcano.

    Volcano feature details
    Information about Mauna Loa displays in the panel. The map zooms to focus on Mauna Loa. This is called the feature's pop-up. Mauna Loa, which last erupted in 1984, is one of three active volcanoes on the island. Mauna Kea is extinct.

  3. Select the volcano's Media tab to see images associated with the volcano.
    Volcano media tab
  4. Select the image of the volcano and select Open Link.

    A large, captioned version of the image opens in the browser.

  5. Close the browser tab with the detailed image. Select Explorer in the upper-left corner to return to the app.
    Back to
  6. Close the pop-up and close the list of features at the volcano's location.
  7. Use Bookmarks Bookmarks to return to the default extent of the map. Dismiss Bookmarks.
  8. Select a lava flow hazard zone, for example, the Kohala Coast, the red area around Hualalai.

    Similar to when you selected the volcano, you may see multiple features at this location. If so, select the hazard area you are interested in.


    If you aren't sure which areas are lava flow hazard zones, turn other layers in the map off to focus on the zones. Use Layers Layers to turn off the other layers.

  9. Similar to when you selected Mauna Loa, you see information about the hazard zone. You can view its media to see images, and select those images to see additional information about them.
    Hazard zone media tab
  10. Close the hazard zone pop-up, and close the list of features if there is one.
  11. On your own, learn more about the volcanos, hazard zones, and emergency shelters on the map. Pinch and stretch with two fingers to zoom in and out on the map.
  12. When you're finished, use Bookmarks Bookmarks to return to a full view of the island. Dismiss Bookmarks.

View the map contents

To work directly with the map layers, you'll use Layers Layers.

  1. Select Overflow Overflow and select Layers Layers to see the contents of the map.
    Layers list

    The order of the layers in the Layers list is the order in which they are drawn on the map. Every layer can be turned on and off.


    Explorer presents the basemap layer separately; you can't turn that layer on and off, but you can view it and change it using another tool. You'll do so later in these steps. Explorer also adds a layer that isn't part of the original map: Markup. You'll learn more about it in the next section.

  2. Use the Lava Flow Hazard Zones toggle to turn the layer off.
    Layers list and map with Lava Flow Hazard Zones 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, but now it is more clear.

  3. Turn off the Terrain layer to see the Topographic basemap.
    Layers list and map with Lava Flow Hazard Zones and Terrain off
  4. Turn the Lava Flow Hazard Zones and Terrain layers back on.
    Layers list with all layers on
  5. Dismiss the Layers list.

Use map tools

You can also work with the map using tools on the toolbar.

  1. On the toolbar, select Overflow Overflow and select Measure Measure.

    The toolbar shows the measure tools, with Measure Distance Measure Distance selected.

    Measure tools

  2. Zoom in on the island to make better use of the space on the screen.
  3. On the map, tap Mauna Loa to start a measurement.
    Measure started at Mauna Loa
  4. Tap another volcano, such as Hualalai, to measure between the two volcanos.
    Measure end
  5. Make a few more measurements. You can continue the one you've started and measure between multiple volcanos, or use Discard Discard to clear your measurement and start again. When you're finished, select Done.
  6. On the toolbar, select Overflow Overflow and select Basemap Basemap to open the Basemaps gallery. Select Oceans or another basemap.
    Basemaps gallery

    The new basemap is shown.

    Map with Oceans basemap
  7. Change the basemap back to the Topographic basemap.
  8. On the toolbar, select Markup Markup.
    Markup tools

    You'll circle Mauna Kea on the map.

  9. Use your finger to draw a circle around the volcano.
    Mauna Kea circled by hand
  10. Select the circle in the pop-up to clean up your drawing, making your sketch into a perfect circle.
    Pop-up to create a circle

    For the pop-up to appear, the shape you drew has to be close to a circle.

    A circle appears around Mauna Kea.

    A perfect circle around Mauna Kea
  11. Select Color and change the color of your circle to green.
    Color tool
    Color selection

    Your markup is now green.

    A green circle
  12. On the toolbar, select GPS GPS off to show your location on the map. If prompted to allow Explorer to access your location, select Allow. If you are not in Hawaii, select GPS GPS on again to center the map on your location.

Next steps

You should now be familiar with the app. Think about how your organization can use Explorer.

Ready to get started with your own maps, and looking for how to make them? Learn more in Make maps.