Site a new hospital

Open and save a map

First, you'll open an existing web map, save a copy, and explore the layers in the map.

  1. Open the Site a new hospital map on ArcGIS Online.

    A map with four layers and a basemap appears.

    The Site a new hospital web map showing Loudoun County, VA, in Map Viewer Classic

    This lesson uses Map Viewer Classic.

  2. At the top of the page, click Sign In and sign in to your ArcGIS organizational account.
    Note:

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

    If you encounter an error or are unable to sign into your account, remember that passwords are case-sensitive. If you forget your ArcGIS password, you can reset your password from the sign in page. See Account Troubleshoot for more information.

    Note:

    To ensure that your user account is set to Publisher or Administrator, at the top of the map, the Analysis tab should be visible, and you can proceed with the lesson

    Analysis on the ribbon

    If the Analysis tab is not visible, you are signed in with a Public Account which does not include access to the Analysis tab.

    Next, you will save a copy of this map in your ArcGIS Online account.

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

    Save As option

  4. In the Save Map window, for Title, type Site a new hospital followed by your initials.
  5. For Tags, type site selection, Loudoun County, hospital, pressing Enter after each tag.
  6. For Summary, type Possible locations for a new hospital in Loudoun County, VA.

    Save Map window

  7. Click Save Map.

    A copy of the map is saved to your ArcGIS account.

  8. Below the ribbon, click Content.

    Content tab below the ribbon

    You'll investigate the data you'll use. The four layers include the location of the current main hospital, the main roads, the urban areas, and the boundary of the county.

  9. Explore each layer by clicking the check box next to each layer to turn it off and on.

Create a buffer around urban areas

Next, you'll create the data to address the first requirement, which is to ensure the new hospital is located within two miles of urban areas. You'll create a new layer that shows a two-mile buffer around the urban areas. A buffer is an area around one or more map features, such as a point, line, or polygon, to a specified distance. The Create Buffer tool is one of the proximity tools that analyze map data based on how close or far away a second feature is. Proximity tools help you answer one of the most common questions posed in spatial analysis: What is near what?

  1. In the Contents pane, point to the Urban Areas layer and click the Perform Analysis button.

    Perform Analysis button

  2. Click Use Proximity.

    Use Proximity option

  3. Click Create Buffers.

    Create Buffers tool

    The Create Buffers pane appears.

  4. For Choose layer containing feature to buffer, confirm that Urban Areas is selected.
  5. For Enter buffer size, choose Distance, type 2, and confirm the unit is set to Miles.
  6. Expand Options.

    Expand Options on the Create Buffers pane

    You'll indicate how you want overlapping buffers to be handled. You'll choose to merge any overlapping areas into one feature.

  7. For Buffer type, choose Dissolve.

    You'll indicate whether you want to keep the features, in this case, the urban areas, in the resulting buffer. You'll choose not to keep them.

  8. For Area of input polygons in buffer polygons, choose Exclude.

    Create Buffers tool parameters

  9. For Result layer name, type BufUrbanAreas2Mi followed by your initials.
  10. Uncheck Use current map extent.

    Result layer name parameter

    Running an analysis tool consumes credits. Credits are the currency used across ArcGIS Online. They are consumed during specific transactions, such as performing analytics, storing features, and geocoding. You can click Show Credits before you run your analysis to check how many credits will be consumed.

    Note:

    You can learn how many remaining credits are in your ArcGIS Online account if your organization administrator has enabled you to view that information. If it is enabled, at the top of the page, click on your username, click My settings. On the My settings page, click Credits to see how many remaining credits are in your account. If it is not enabled, contact your organizational account administrator.

  11. Click Run Analysis.

    After a few moments, the new layer is added to the top of the Contents pane and drawn on the map. The blue areas show the two-mile buffer around the urban areas.

    Map with buffered urban areas

  12. On the ribbon, click Save and choose Save.

Create drive-time areas around the main hospital

To address the second requirement for the new hospital to be located more than a 20-minute car ride from the existing main hospital, you'll create drive-time areas. A drive-time area is the area that can be reached within a specified travel time or travel distance along a street network based on travel mode. Travel mode refers to different ways of moving along a street, such as driving a car, riding a bike, taking a bus, or walking.

The Create Drive-Time Areas tool is also a proximity tool. Like the Create Buffer tool, it analyzes map data based on how close or far away features are, but it does so along a street network.

  1. In the Contents pane, point to the Main Hospital layer, click Perform Analysis.
  2. Click Use Proximity.
  3. Click Create Drive-Time Areas.

    Create Drive-Time Areas tool

    The Create Drive-Time Areas pane appears.

  4. For Choose point layer to calculate drive-time areas around, confirm that Main Hospital is selected.
  5. For Measure, confirm that Driving Time is selected, type 20, and confirm the unit is set to Minutes.

    You want to identify locations from which county residents can access the hospital within a 20-minute drive.

  6. For Travel direction, choose Towards Facility.

    Create Drive-Time Areas parameters

    You'll indicate how you want areas from different points to be handled. You'll choose to dissolve any overlapping areas into one feature.

  7. For Areas from different points, choose Dissolve.
  8. For Result layer name, type Drive20MinHospital followed by your initials and uncheck Use current map extent.

    Areas from different points and Result layer name parameters

  9. Click Run Analysis.

    ArcGIS Online uses a detailed up-to-date road network to perform the analysis. It does not use the main roads layer you see on the map.

    After a few moments, the new layer is added to the top of the Contents pane and drawn on the map.

  10. On the Contents pane, uncheck the Urban Areas and BufUrbanAreas2Mi layers so you can better see the new layer you created.

    The dark purple shows the area from which people can drive to the main hospital in 20 minutes or less.

    Drive-time areas map

  11. Save your map.

Create a buffer around main roads

To address the third requirement that the new hospital must be located within one mile of main roads, you'll create a buffer around the main roads.

  1. On the Contents pane, point to the Roads layer and click Perform Analysis.
  2. Click Use Proximity and click Create Buffers.
  3. For Choose layer containing features to buffer, confirm Roads is selected.
  4. For Enter buffer size, confirm Distance is set to 1 and Miles is the selected unit.

    Create Buffers parameters

  5. Under Enter buffer size, expand Options.
  6. For Buffer type, choose Dissolve. Confirm Side type is set to Around and End type is set to Round.
  7. For Result layer name, type BufRoads1Mi followed by your initials.
  8. Uncheck Use current map extent.

    Buffer type options

  9. Click Run Analysis.

    After a few moments, the new layer is added to the top of the Contents pane and drawn on the map.

  10. Ont he Contents pane, uncheck the Drive20MinHospital layer.
  11. On the Contents pane, turn on all the layers.

    Road buffers map

    The BufRoads1Mi layer and the urban areas buffer layer are hard to distinguish, since they are similar shades of blue. To make them easier to discern, you'll change the symbol for the roads buffer layer.

  12. Point to the BufRoads1Mi layer and click the Change Style button.

    Change Style button

  13. For Choose an attribute to show, confirm Show location only is selected.
  14. For Select a drawing style, click Options.

    Location (Single symbol) Options button

  15. Click Symbols.

    Symbols button

  16. For Fill, choose dark gray (#858585).

    Gray fill color

    Next, you will adjust the transparency setting so the layers under the BufRoads1Mi layer are more visible.

    Changing the transparency, or opacity, of a layer in a map allows you to see more, or less, of the underlying layers. The more transparent a layer is, the less visible it appears on the map and the more visible the other layers appear. In other words, the greater the transparency setting, the more see-through the layer will appear, like a stained-glass window. The smaller the transparency setting, the harder the layer is to see through, like a curtain or drape covering a window.

  17. For Transparency, set the slider to about 25 percent.

    Transparency slider at around 25 percent

  18. Click the Outline tab and choose the black color (#1A1A1A). Confirm that Line Width is set to 1.33 px.

    Black outline color

  19. Click OK.
  20. In the Change Styles pane, click OK and click Done.

    The dark gray shows the area within one mile of the main roads.

    Symbolized road buffers map

  21. Save your map.

Combine buffers and drive-time areas

Next, you'll combine the layers you created to identify only those areas that meet the three requirements. You'll use the data management overlay layer tools; these tools work on two layers at a time, so you'll use them multiple times.

First, you'll combine the buffered urban area layer and the 20-minute drive-time layer.

  1. In the Contents pane, turn off the BufRoads1Mi, Main Hospital, Roads, and Urban Areas layers.

    Urban area buffers and drive-time areas map

    Review your map and consider the areas that are within two miles of urban areas and are more than a 20-minute car ride from the main hospital. How would you describe in words how to get only those areas? You might say you want to subtract the drive-time area from the buffered urban areas. That's what the Erase tool does.

    You will use the Erase tool to create a new layer only includes the areas in the BufUrbanAreas2Mi layer that do not overlap with the Drive20MinHospital. This new layer will only contain the portions of the BufUrbanAreas2Mi layer that are outside the Drive20MinHospital layer drive-time areas.

  2. For the BufUrbanAreas2Mi layer, click the Perform Analysis button.
  3. Click Manage Data and choose Overlay Layers.

    Overlay Layers tool

  4. For Choose input layer, confirm BufUrbanAreas2Mi is selected.
  5. For Choose overlay layer, choose Drive20MinHospital.
  6. For Choose overlay method, choose Erase.

    Erase chosen for the Choose overlay method

  7. For Result layer name, type Suitable1 followed by your initials.
  8. Uncheck Use current map extent.

    Overlay Layers parameters

  9. Click Run Analysis.

    After a few moments, the new layer is added to the top of the Contents pane and added to the map.

  10. Turn off Drive20MinHospital and BufUrbanAreas2Mi.

    The Suitable1 layer includes areas within two miles of urban areas but does not include areas within a 20-minute car ride to the main hospital.

    Other layers turned off on the map

  11. Save your map.

Create a layer that addresses all requirements

Next, you'll combine the result of the last step, the Suitable1 layer, and the buffered roads layer to create a layer that addresses all three requirements. You will use the Intersect tool to accomplish this. The Intersect tool creates a new layer that shows the areas that overlap between two layers. The new layer will be the area where the Suitable1 layer and BufRoads1Mi layer overlap.

  1. In the Contents pane, turn on the BuffRoads1Mi layer.

    Buffered roads and suitable areas on the map

  2. For the Suitable1 layer, click the Perform Analysis button.
  3. Click Manage Data and choose Overlay Layers.
  4. For Choose input layer, confirm that Suitable1 is selected.
  5. For Choose overlay layer, choose BufRoads1Mi.
  6. For Choose overlay method, choose Intersect.
  7. For Result layer name, type Suitable2 followed by your initials and uncheck Use current map extent.

    Overlay Layers parameters

  8. Click Run Analysis.

    After a few moments, the layer is created and added to the top of the Contents pane.

    Second suitability layer on the map

  9. On the Contents pane, turn off the Suitable1 and BufRoads1Mi layers.

    Map showing only the second suitability layer

  10. Save the map.

    The areas in the Suitable2 layer meet all three requirements for locating the new hospital. Is there another criterion, one that was not explicitly stated, that has not been addressed? Look at the boundary of Loudoun County. Some of the areas are not in Loudoun County. You'll use the Intersect tool to address that issue next.

Find suitable areas in the study area

Finally, you'll perform one last analysis to find areas that meet the three stated requirements and are within Loudoun County.

  1. For the Suitable2 layer, click the Perform Analysis button.
  2. Click Manage Data and choose Overlay Layers.
  3. In the Overlay Layers pane, confirm the following:
    • For Choose input layer, confirm that Suitable2 is selected.
    • For Choose overlay layer, choose Loudoun County.
    • For Choose overlay method, choose Intersect.
  4. For Result layer name, type Suitable3 followed by your initials and uncheck Use current map extent.

    Overlay Layers parameters

  5. Click Run Analysis.

    After a few moments, the layer is created and added to the top of the Contents pane.

  6. In the Contents pane, turn off the Suitable2 layer.

    Final result layer on map

  7. Save your map.

    The Suitable3 layer represents the areas in Loudoun County that meets the provided requirements for a new hospital location.

In this lesson, you created data layers using proximity and data management tools. You created buffers and drive-time areas to identify areas within a time or a distance from map features. You then combined these new layers, and the boundary of Loudoun County, using overlay layer tools to create a layer that includes areas that meet the spatial requirements.

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