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Create a map

To help the local search and rescue (SAR) team prepare for a missing person search operation in Yosemite National Park, you'll create a web map. This map will contain static reference layers and dynamic incident data that can be edited over the course of an incident to keep the map up to date.

This scenario is based on a fictional case study named Wilderness Search Strategy and Tactics by Phillips et al., published in 2014 in the journal of Wilderness & Environmental Medicine.

Navigate to the area of interest

A web map is an interactive display of geographic information that you can use to tell stories and answer questions. Maps contain a basemap, a set of data layers (many of which include interactive pop-up windows with information about the data), an area of interest (map extent), and navigation tools to pan and zoom.

You'll create a new map and navigate to Yosemite.

  1. Sign in to your ArcGIS organizational account or into ArcGIS Enterprise using a named user account.

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

  2. On the ribbon at the top of your organization home page, click Map.

    Map tab on ribbon

    A new map opens. The map extent for a new map is set to the default extent of your organization. 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 left of the map is the Details pane, which provides information about the map and its layers. Drag the map to pan it and scroll the mouse wheel to zoom in and out.

    In case your basemap isn't set to Topographic by default, you'll change the basemap now.


    The Topographic basemap is sometimes more current than other basemap options, such as USA Topo Maps. The available basemaps differ based on organizational settings. If your organization's available basemaps aren't sufficient, contact your organization administrator and ask them to configure the basemap gallery.

  3. If necessary, on the ribbon, click Basemap and choose Topographic.

    Topographic basemap option

  4. On the ribbon, in the search box, type Yosemite National Park. In the list of suggested locations, click Yosemite National Park, CA, USA.

    Search for Yosemite National Park


    Some ArcGIS organizations have custom address locators. You may encounter different search results than those in the example image.

    The map zooms to Yosemite National Park in California. The Search result pop-up confirms the location.

    Yosemite search result pop-up

  5. Close the Search result pop-up.

    You'll bookmark this location so you can quickly navigate back to it if needed.

  6. On the ribbon, click Bookmarks and click Add Bookmark.

    Add Bookmark option

  7. Type Yosemite National Park and press Enter. Close the Bookmarked places window.

    Any time you choose this bookmark, your map will automatically navigate back to the current map extent.

    Before you continue, you'll save the map.

  8. On the ribbon, click Save and choose Save As.

    Save As option

    The Save Map window appears.

  9. For Title, type Yosemite Search and Rescue. For Tags, type SAR, National Park Service, and California (press Enter after typing each tag). For Summary, type This map contains base and incident data to assist search and rescue teams in Yosemite National Park, California.
  10. Click Save Map.

Add reference layers

Next, you'll add data layers to your map to serve as the base data. Like the basemap, your base data will include static layers that provide geographic context. These layers will be more specific to SAR concerns in the Yosemite area, as opposed to the more general data of the basemap.

First, you'll add a layer of Public Safety Answer Point (PSAP) 911 Service Area Boundaries from the Homeland Infrastructure Foundation-Level Data (HIFLD). A PSAP is a facility equipped and staffed to receive emergency calls (in the United States, these calls use the number 911). The PSAP service area is the geographic area within which a 911 call placed using a landline is answered at the associated PSAP.

When a person is reported missing, SAR teams often work with the local PSAP to gather information from the reporting party, or even directly from the missing person if they called 911. Knowing the service areas at a glance will provide useful reference information for a search.

  1. On the ribbon, click the Add button and choose Browse Living Atlas Layers.

    Browse Living Atlas Layers option

    The ArcGIS Living Atlas of the World is Esri's collection of authoritative geographic information from around the world. It contains many worldwide, national, and local datasets.

  2. Click Search for layers, type PSAP 911 Service Area Boundaries, and press Enter.

    The search returns a layer of the same name by jrayer_geoplatform.


    To learn more about a layer before you add it, click its name in the list of search results to open a pane with a description of the layer. For even more information, in the description pane, click the button next to the layer name to open its details page.

  3. For the PSAP 911 Service Area Boundaries layer, click the Add button.

    Add button

    The layer is added to the map. Most of the map extent is covered by a single service area. The service areas obscure the basemap. Later, you'll turn this layer off to better see the basemap. For now, you'll continue adding layers.

    The Emergency Medical Service (EMS) Stations dataset contains locations where EMS personnel are stationed or where EMS equipment is stored. Knowing these locations will help SAR teams determine the closest ambulance to a victim once they have been found and transported to a road access point. (In some situations, helicopters are used to transport victims, so collecting helicopter landing zone data may also be useful.)

    The EMS dataset is not hosted in the Living Atlas, so you'll change the extent of your search.

  4. Click Living Atlas and choose ArcGIS Online. Clear the existing search text, type Emergency Medical Service (EMS) Stations owner:Learn_ArcGIS, and press Enter.
  5. In the list of results, for the Emergency Medical Service (EMS) Stations layer by Learn_ArcGIS, click the Add button.

    The layer is added to the map. There are only a few EMS stations near Yosemite. Most EMS stations are located near populated areas, so when people are injured in a national park, it can be difficult to get aid to them quickly.


    If you want, zoom out on the map once or twice to see the location of nearby EMS stations. You can always return to the default extent with the bookmark you created or the Default extent button.

    Next, you'll add a minimum essential dataset (MED). A MED contains base data that is essential to most of your SAR team's missions. It generally includes geographic data like trails and water bodies unique to your geographic area. For many areas, you would need to contact local land management agencies to request access to this data. For Yosemite National Park, you'll access a dataset compiled from the publicly accessible National Park Service Data Store.

    This MED includes the following layers:

    • Campgrounds
    • Place-names
    • Trailheads
    • High Sierra and Backcountry Huts
    • Trails
    • Rivers
    • Roads
    • Water bodies
    • Yosemite National Park boundary


    When compiling base data for local areas in the United States, consider searching the Local Data Resources web app.

  6. Clear the existing search text, type Yosemite MED owner:Learn_ArcGIS, and press Enter.

    Search ArcGIS Online for Yosemite MED

  7. In the list of results, for Base Data - Yosemite National Park MED, click the Add button.

    Nine new layers are added to your map.

    Yosemite MED layers

    Last, you'll add a layer of watershed boundaries. According to evaluations of lost person behavior, terrain impacts the distance a missing person may travel from the Initial Planning Point (IPP). The IPP is the location a missing person was last known to be, and usually where SAR teams begin their operations.

    A watershed is the land area or topographic region that drains into a water body. It provides a natural geographic area for SAR planning. In Yosemite National Park, 86 percent of missing persons were found within or adjacent to the watershed of the IPP (Doke 2012).

    You'll add this layer by searching for its unique item ID.

  8. Clear the existing search text, type (or copy and paste) 0f76175ca3a4424a9ce2328b1daf931a, and press Enter.

    The search returns a single result, Watershed Boundary Dataset: HUC 12s by Esri.

  9. Click the Add button to add the result to the map.

    The layer is added to the map.

  10. In the search pane, click the Back button.

    Back button

  11. In the Details pane, click the Show Contents of Map button.

    Show Contents of Map button

    The Contents pane appears. This pane lists all the layers on the map. You can turn layers off to hide them. For now, you'll turn off some of the layers to better see other layers.

  12. In the Contents pane, uncheck the Watershed Boundary Dataset: HUC 12s, Emergency Medical Service (EMS) Stations, and PSAP 911 Service Area Boundaries layers.

    Next, you'll change some of the properties of the layers you added. You'll reorganize them in the list of layers so that certain layers appear above others on the map. You'll also rename them to convey only the most important information.

    First, you'll move the watershed boundaries under most of the other data. For map legibility purposes, it is generally recommended that polygon data (such as the boundaries of areas) appear under data conveyed only as lines and points.

  13. In the Contents pane, point to the Watershed Boundary Dataset: HUC 12s layer and drag the reorder button so that the layer is moved under the Emergency Medical Service (EMS) Stations layer but above the PSAP 911 Service Area Boundaries layer.

    Reorder watershed boundaries layer

    Next, you'll rename the Base Data - Yosemite National Park MED layers. Each of these nine layers has repetitive information about the layer's source dataset in the layer name. You'll shorten the names to convey only the most relevant information.

  14. Point to the Base Data - Yosemite National Park MED - Campgrounds layer. Click the More Options button and choose Rename.

    Rename option

    The Rename window appears.

  15. Change the name to Campgrounds and click OK.
  16. Rename the eight remaining MED layers to remove Base Data - Yosemite National Park MED from the layer name.
  17. Save the map.

Create an incident data layer

Next, you'll add an editable, dynamic layer to track incident data. Because this layer will be unique to Yosemite's SAR operations, you can't add an existing layer from the Living Atlas. Instead, you'll create a new feature layer based on a template. This template contains symbols and attributes recommended by the NAPSG Foundation SAR Working Group. The template itself, known as MapSAROnline, has already been added as a feature service to ArcGIS Online.

When you create a layer based on this template, it will not have any features (such as points, lines, or polygons), but you'll be able to edit it to add them as needed.

  1. Next to the map name, click Home. Right-click Content and choose Open link in new tab (or your browser's equivalent option).

    Open link in new tab option

    Your Content page opens in a new tab. This page contains all the maps, layers, and other items saved in your account.

  2. In your Content page, click Create and choose Feature Layer.

    Feature Layer option in Create menu

    The Create a feature layer window appears. You'll create a feature layer using a URL to the service based on the MapSAROnline template.

  3. Click From URL and paste the following URL:

  4. Click Next.

    The window loads a list of layers that will be included in the new feature layer based on the template you provided. You'll keep all of these layers.

  5. Click Next.

    Next, you'll choose the map extent for the layer.

  6. Pan and zoom to Yosemite National Park (in California, east of San Francisco and south of Carson City).

    To make sure your extent is correct, check the coordinates under the map. Your coordinates should be similar to the following coordinates:

    • Left should be near -120.
    • Right should be near -118.
    • Top should be near 38.
    • Bottom should be near 37.

    Extent for feature layer

  7. Click Next.
  8. For Title, type Yosemite National Park SAR Incident Data Layer and add your name or initials to the end. For Tags, type Search and Rescue and California.
  9. Click Done.

    After a few moments, the layer is created. The layer's details page opens with information about the layer. You're almost ready to add the layer to your map, but first you'll enable editing on the layer.

  10. On the ribbon, click Settings.

    Settings option

  11. Click Feature Layer (hosted). Confirm that Enable editing is checked.

    Enable editing option

  12. Close the browser tab of the details page and return to the browser tab of the map. On the ribbon, click the Add button and choose Search for layers.
  13. Confirm that My Content is chosen. Search for and add the Yosemite National Park SAR Incident Data layer.
  14. Click the Back button.

    The feature layer you created contains 13 incident data layers. As with the MED layers, you'll rename these layers to convey important information more quickly.

  15. Rename each of the new layers to remove the text Yosemite National Park SAR Incident Data Layer from the layer name. Confirm that the following layers were added:
    • Initial Planning Point (and subject information)
    • SAR Team
    • Reporting Party
    • Found or Suspension
    • Clue Points
    • Cellphone Pings
    • Assets
    • Routes
    • Search Area Other
    • Search Area Statistical
    • Search Area Theoretical
    • Assignment Status
    • Search Planning Areas

    These layers represent different dynamic elements of a SAR operation. They will need to be tracked and edited as the operation develops.

  16. Save the map.

Automate area calculations

One of the incident data layers is named Assignment Status. The purpose of this layer is to create search assignment areas. When deciding which areas to search, SAR teams must consider how large the area is to determine whether it can be searched in a reasonable amount of time. Although terrain affects how quickly a location can be searched, a general guideline is that a search area should be around 0.25 square miles (or about 0.65 square kilometers).

You'll create a custom pop-up for this layer that uses an Arcade expression to automatically calculate the area of a feature.

  1. In the Contents pane, point to the Assignment Status layer, click More Options, and choose Configure Pop-up.

    Configure Pop-up option

    The Configure Pop-up pane appears.

  2. Under Attribute Expressions, click Add.

    An Arcade expression window appears. The default name of the expression is Custom.

  3. Next to Custom, click Edit. Change the name to Area (Sq. Km) and click Save.

    There are a wide variety of possible Arcade expressions. Your expression will be relatively simple. It'll use a function named AreaGeodetic that calculates area. You'll specify that the area will be calculated for the feature that is clicked and the measurement will be given in square kilometers.

  4. For Expression, type (or copy and paste) the following expression:

    AreaGeodetic($feature, 'square-kilometers')

    Expression to calculate feature area

  5. Click OK. In the Configure Pop-up pane, click OK.

    The layer has no features yet, so you can't test the pop-up right away. Another layer is the Routes layer. This layer will contain line features that indicate important routes. Knowing the lengths of the routes is important, so you'll create another expression to automatically calculate length.

  6. In the Contents pane, point to the Routes layer, click More Options, and choose Configure Pop-up.
  7. Under Attribute Expressions, click Add. Change the name of the new expression to Distance (Km).

    This expression will use a function named Length. This function operates similarly to the AreaGeodetic function but calculates length instead of area.

  8. For Expression, type (or copy and paste) the following expression:

    Length($feature, 'kilometers')

    Expression to calculate feature length

  9. Click OK. In the Configure Pop-up pane, click OK.
  10. Save the map.

    Last, you'll share the map. You can choose to keep a map private, share it with your organization, or share it with everyone. You'll want members of the SAR team to be able to access the map, but some information in a missing person search may be sensitive. You'll share the map with your organization.

  11. On the ribbon, click Share.

    Share button

  12. In the Share window, check your organization name.

    The Update Sharing window appears. This window prompts you to share the map's layers with the same permissions the map has.

  13. Click Update Sharing.

    The watershed boundaries layer is subscriber content and may not be accessible to certain accounts in your web map.

  14. Click Done.

In this lesson, you created and configured a new web map with reference data and dynamic incident layers. Your map is suitable for a SAR operation in Yosemite National Park. In the next lesson, you'll use this web map to create a web app to provide preconfigured and ready-to-use GIS tools to the SAR team.