In this lesson, you'll create a map that shows hurricane evacuation routes in Houston, Texas. First, you'll begin a new map in ArcGIS Online and locate Houston. Then, you'll add a map layer that shows evacuation routes. Lastly, you'll change the way your map and layers look to better display the data.
Begin a map
You'll begin your map by signing in and navigating to your area of interest: Houston, Texas.
- Sign in to your ArcGIS account.
- On the ribbon, click Map.
The example images assume you have a public account. If you're using a trial or organizational account, you may encounter differences.
A new map opens.
If you're in a new session, clicking Map will open a new map. Otherwise, it will open an existing map (the last map you were using). If an existing map opens, click New Map, and choose Create New Map.
Your map's appearance varies based on your account or organizational settings and your browser window size. It may show the United States (like in the example image), the world, or another extent. The only layer on the map is the basemap, which provides geographic context such as water bodies and political boundaries. The default basemap is Topographic, but your map may have a different basemap depending on your organization's settings.
Above the map is the ribbon. To the side of the map is the Details pane, which provides information about the map and its layers. Next, you'll navigate to your area of interest.
- On the ribbon, in the search box, type Houston. In the list of suggested locations, click Houston, TX, USA.
Some ArcGIS organizations have custom address locators. You may encounter different search results than those in the example image.
The map zooms to Houston. A Search result pop-up confirms the location.
- Close the Search result pop-up.
Add a layer
Next, you'll add a layer to your map that shows hurricane evacuation routes in Houston. You'll add this layer from the ArcGIS Living Atlas of the World, a collection of curated geographic data from around the globe.
- On the ribbon, click Add and choose Search for Layers.
If you have an organizational account, the Add menu also contains the Browse Living Atlas Layers option. You can use this option to more directly search for the layer you want, although the steps to do so are slightly different.
The Search for Layers pane opens. The layer you want to add is owned by the Federal User Community, an ArcGIS account that contains United States governmental data. You can find the layer more easily by adding the name of the layer's owner to the search terms.
- For Find, type Hurricane Evacuation Routes. Then, type owner:Federal_User_Community.
- If necessary, for In, choose ArcGIS Online.
- Click Go.
The search returns a single result.
- For the Hurricane Evacuation Routes layer, click Add.
The layer is added to the map.
The routes are displayed as dark gray lines that travel throughout the city, but they don't stand out clearly against the Topographic basemap. You'll change the basemap to one with a lighter color scheme so the routes stand out.
- In the Search for Layers pane, click Done Adding Layers.
The Contents pane opens. It lists all layers on the map, including the basemap.
- On the ribbon, click Basemap and choose Light Gray Canvas.
Some ArcGIS organizations may have different default basemaps. If you don't see the Light Gray Canvas basemap, click Add and choose Search for Layers. For Find, type World Light Gray owner:esri and press Enter. Add the World Light Gray Base and World Light Gray Reference layers. Then, in the Contents pane, click the More Options button for each layer and choose Move to Basemap.
The basemap changes. The evacuation routes stand out much more against the lighter-colored, less detailed basemap.
Navigate the map
Before you continue, it's a good idea to explore the map and familiarize yourself with Houston's geography. With a better understanding of the area, you'll be better informed to make decisions and draw conclusions later on. Before you explore, you'll create a bookmark of the current extent so you can quickly return to it when needed.
- On the ribbon, click Bookmarks and choose Add Bookmark.
A text box for the bookmark's name appears.
- In the text box, type Houston and press Enter.
The bookmark is added. You can choose this bookmark to automatically navigate to the map extent where the bookmark was created.
- Close the Bookmarked places window.
You're now ready to explore the city.
- Zoom in to the center of the city, near the Houston label, until the Buffalo, Brays, and White Oak Bayous appear on the map.
There are several ways to zoom. You can click the Zoom In button in the corner of the map or scroll up with the mouse wheel. Alternatively, you can press Shift while drawing a box around the area you want to zoom to.
- If necessary, pan the map until all three bayous are visible.
Houston has several major bayous (flat, low-lying marshes or wetlands). During a hurricane, these bayous are prone to flooding and can become especially dangerous. You may want to keep this area in mind when you later identify high-risk areas.
- Add a bookmark for the current map extent. Name the bookmark Bayous.
- On the ribbon, click Bookmarks and choose Houston.
The map zooms to its original extent.
Change the style
Although the evacuation routes stand out more against the light basemap, they could be even more eye-catching. You'll change the layer's style (also known as its symbology) to give the routes a brighter color and a thicker line width.
- In the Contents pane, point to the Hurricane Evacuation Routes layer and click the Change Style button.
The Change Style pane opens. Layers can have either a single symbol or multiple symbols based on attribute information such as names or speed limits. You'll learn more about attribute information later. Right now, you're only interested in showing the location of roads, not particular characteristics of each road, so you'll continue to symbolize the layer with a single symbol.
- For Location (Single symbol), click Options.
The pane changes to provide multiple style options, such as the layer's transparency or the range of map extents at which it is visible. You'll change the color and size of the symbol itself.
- Click Symbols.
A window opens with a color palette and other options.
- On the color palette, choose the blue color on the bottom row, fourth column from the right.
After you choose the color, the six-character hexadecimal code changes to #004C73.
- For Line Width, choose 3 px.
- Click OK.
The new line color and width are applied to the layer.
- In the Change Style pane, click OK. Then, click Done.
With the thicker, brighter symbol, the routes are eye-catching and stand out.
The routes layer is a feature layer, which means it consists of individual features with distinct characteristics. In this case, each route segment is a feature. You can view a feature's characteristics, also known as its attribute information, by clicking the feature on the map and opening its pop-up.
- Click a segment of an evacuation route.
Its pop-up opens.
From the pop-up, you learn name of the route (in the example image, I-45), as well as whether the route is paved and what type of road it is. The owner of the Hurricane Evacuation Routes layer specifically configured this pop-up to present attribute information in a clear and readable way. You'll learn how to configure pop-ups in a later lesson.
- Click a few different route segments to view their pop-ups. When finished, close the pop-up.
Save and share the map
Next, you'll save your evacuation map and assign it a title, tags, and a summary to make it easy to find and identify later. Then, you'll share the map to make it accessible to the public.
- On the ribbon, click the Save button and click Save As.
The Save Map window opens.
- For Title, type Houston Evacuation Map.
Next, you'll add tags. Tags are terms that allow users to search for your map on ArcGIS Online.
- For Tags, type each of the following tags, pressing Enter after each one:
- Evacuation Routes
The summary appears on your map's details page and should provide information so users better understand your map's purpose.
- For Summary, type This map shows hurricane evacuation routes in Houston, Texas.
- Click Save Map.
The map is saved. It now appears in your account's content. You can access your content by clicking ArcGIS (if using a public account) or Home (if using an organizational account) and choosing Content. For now, you'll share the map with the public.
- On the ribbon, click the Share button.
- In the Share window, check Everyone (public).
If you are using an organizational account, your map will also be shared with your organization.
- Click Done.
You can also feature your map on a public-facing website by embedding the map. In the Share window, click Embed in Website and choose the map options and symbols you want. Then, copy the HTML code provided and paste it into your web page.
In this lesson, you located the city of Houston and added a layer showing hurricane evacuation routes. Then, you changed the basemap and the style of the routes. Finally, you saved your map and shared it with the public.
Web maps often include multiple layers of data to highlight spatial patterns and relationships. In the next lesson, you'll add a layer of Houston demographic data and identify vulnerable areas in need of evacuation assistance.