Identify potential shelter locations
During Hurricane Harvey, there was not enough space in shelters for everyone escaping the widespread flooding. ArcGIS Business Analyst Web App can be used to determine both potential shelter locations and populations in need. You'll create a project in Business Analyst and add data to it, including existing shelter sites and areas of the city designated as likely to flood. Then, you'll add the locations of schools within the city, as these are facilities that are easy to convert into shelters. Finally, you'll begin narrowing down the schools. Shelters shouldn't be too small, and they should be relatively safe from floodwaters, usually sitting outside of both evacuation zones and FEMA-designated floodplains.
Create a project
Projects are the way Business Analyst organizes and groups together relevant content. For this project, you'll be using point and site data as well as ArcGIS Online layers. These can be added in several ways and are stored in the project pane.
- Sign in to Business Analyst.
The Business Analyst home page opens. On this page, you can see recent updates and a quick-start video, as well as your own content. If you have used Business Analyst before, your latest content will be displayed at the bottom of the screen.
Business Analyst requires a licensed ArcGIS organizational account. If you are the administrator of your organization, you can assign yourself a license. Otherwise, you'll need to contact your administrator for permission.
- Click Get Started Now.
The Maps tab opens. If you have used the app before, your projects will be shown under My projects.
- Click Create Project.
The Create Project window opens.
- Name the project Emergency Shelter Locations and click Create.
A window opens, explaining that a new project is being created. The process might take a few minutes.
Once the project is complete, another window opens for confirmation.
- In the confirmation window, click OK.
The Maps tab has been updated to show your new project.
- If Emergency Shelter Locations is not automatically selected, point to the card and click Open.
- Close the project pane.
Your new project opens.
- If necessary, close the Step-by-Step Guided Tours pop-up.
Next, you'll add data to your new project. There are several ways to add data. The first is a spreadsheet of current shelter locations in Houston. The addresses are saved in a spreadsheet, which you'll upload to Business Analyst. Then, you'll add web maps of evacuation zones and floodplains.
- Download the houston-shelters CSV file.
- On the ribbon, click Add Data and choose Import File.
The Import File pane opens in place of the project pane.
- Click Browse and locate the houston-shelters CSV file.
- Click Import.
The location fields are automatically populated with the corresponding column from the spreadsheet.
- Confirm that the address and ZIP fields are correct. Click Next.
In the second step, you can choose how your data is displayed. Because the spreadsheet contains only address points, the default drawing style is Location (Single Symbol).
- Click Next.
Finally, you'll save the points to the project.
- Confirm that the Save only points option is selected and click Apply.
- Click I'm Done.
During Hurricane Harvey, there were 38 shelters available. Depending on the map scale you're using, the shelters might be displayed using clustering. Due to proximity, several shelters can be represented by a single pin with the number of points in a box to the upper left. This feature is scale dependent and will disappear as you zoom closer.
- On the ribbon, click the Emergency Shelter Locations tab.
The project pane opens. Houston Shelters has been saved under Other Layers. The check box next to the layer indicates that it is currently being drawn on the map.
- Uncheck the houston-shelters layer.
The layer will still be available for analysis, but it won't show on the map. Now you'll add two web maps with the other data you'll need for your analysis. One shows FEMA-designated floodplains. The other shows evacuation zones for the city. Because these areas are prone to flooding, no shelters should be located within them.
- On the ribbon, click Add Data and choose Web Maps and Layers.
The Web Maps and Layers window opens.
- Click the ArcGIS tab.
- In the search bar, type usa flood risk and press Enter.
Numerous results include USA Flood Risk in their names.
- Hover over the results and choose the USA Flood Risk (Mature Support) result that is a map service published by Esri.
The other result, the image service layer, is the raster version of the USA flood risk data. This raster layer has a resolution of 30 meters, which means that its data is stored in cells that are 30 meters by 30 meters in dimension. This is useful when working on a national scale, but when you're looking at a relatively small area, like Houston, 30 meters can be the difference of an entire building.
- Click Add.
- If necessary, zoom to Houston.
Because the data is so detailed, it will only draw at large scales. This layer represents FEMA's Flood Insurance Rate Maps and shows areas where the annual likelihood of a flood is 1 percent or greater.
Next, you'll add the evacuation zones layer.
- In the project pane, uncheck USA Flood Risk (Mature Support) to turn it off.
- Click Add Data again and choose Web Maps and Layers.
- In the search bar, paste the URL for a web map of evacuation zones in Houston. (https://services2.arcgis.com/j80Jz20at6Bi0thr/arcgis/rest/services/Harris_County_Hurricane_Evacuation_Zones/MapServer) and press Enter.
The web map is added to the project. If you know the URL or ID of your web map, you can use the Web Maps and Layers window to locate and add it.
The evacuation zone layer shows evacuation data for all of Harris County, where Houston is located.
- Click the arrow in the search bar and choose Add a boundary.
If you don't see a search bar, resize your window.
- In the search bar, type Houston, TX and press Enter.
A list of search results opens. Because you want to analyze data in Houston, the best match is Houston City, Texas.
- Click Houston City, TX.
The map zooms to Houston, drawing the city boundary.
- Close the Place window.
Now that you have the city limits, you'll identify parts of the city that lie within evacuation zones and floodplains. Facilities in flood-prone places can immediately be removed from your list of shelter candidates.
Business Analyst automatically saves your project. If you need to return to it, click the Maps tab on the home page and choose the Emergency Shelter Locations project card. Projects do not save maps, though. To redraw your map, click the Emergency Shelter Locations tab on the ribbon and turn on layers.
Map school locations
The last dataset you need is the locations of all the elementary and secondary schools in Houston. From this list, you'll start identifying potential shelters using visual analysis of schools that lie within areas of likely flooding. Locations should not be considered for shelters if they overlap with hurricane evacuation zones or FEMA-designated floodplains.
- On the ribbon, click Create Maps from Data.
- Choose Business and Facilities Search.
The Business and Facilities Search pane appears on the left side of the window.
- Click More options.
Now in addition to being able to search by name, you can search using other options. One option is North American Industry Classification System (NAICS)-based code, a system of facility classification that the United States Census Bureau uses to classify industries. Using this code results in a more accurate search because it narrows the results with much greater accuracy than a keyword search.
- Click NAICS code directory.
The United States Census website opens to the directory in another tab. The NAICS directory lists identifying codes for each industry. These are the broadest classifications of industry. Individual occupations can be found by clicking the corresponding industry code.
- On the 2017 NAICS page, click the number 61 for Educational Services.
Another window appears with all the occupation and business types within the educational services category. This category includes colleges, trade schools, flight schools, and more. Based on your criteria, the ideal facilities are elementary and secondary schools. The NAICS code for these types of schools is 6111.
- Return to the Business Analyst app. In the Business and Facilities Search pane, for NAICS-based code, type 6111.
- For Search extent, choose the boundary for Houston City, TX.
- For Search limit, choose the maximum of 5000 results.
- Click Go.
The results are added to the map and listed in the search pane on the left side of the window. There are approximately 900 primary and secondary schools in Houston. In the pane, you can further refine the results to select the best candidates.
Demographic data is updated periodically. Your results throughout the lesson may differ.
- Scroll down to the Number of Employees box. For the minimum, type 125. Press Enter.
The search results update to show approximately 60 facilities that meet the employee requirement. The number of employees a facility has is a reasonably good indicator of how large the facility is. Only larger schools are good candidates, because shelters need to be able to hold large numbers of people.
Now that you've narrowed the results, they no longer need to be clustered. To more easily perform the next few steps, you'll turn off clustering so each school gets its own pin on the map.
- Click Next.
- In the Style and save search results step, uncheck the Cluster points box.
Each of the schools is drawn on the map. However, these results still include points in both the evacuation zone and the floodplain (the colorful buffer zones). Next, turn off the Houston city boundary. Before you save the layer, remove these facilities by drawing a bounding rectangle around them.
- On the toolbar, click the Clear map button.
- In the Clear Map window, check the box for Houston City, TX and click Clear.
The yellow boundary line is removed from the map. Now it won't be selected with the school locations when you draw the bounding box.
- While pressing the Shift key, drag a rectangle on the map over the evacuation zone. (You may want to zoom in to the evacuation zone so you can get a more accurate bounding box.)
The points are added to the selection.
- In the Selection window, click Remove these points.
The selected schools are removed from the map. Depending on how you drew your bounding rectangle, you may still need to remove points. Repeat the selection process until all points in the evacuation zone are gone. Then, you'll switch layers and use the same process to remove the schools that lie within floodplains.
To select a single point, you can click the pin rather than drawing a bounding rectangle over it.
- In the project pane, turn on the USA Flood Risk (Mature Support) layer (floodplains) and turn off the evacuation zones layer. Click Close.
To open the project pane, click the Emergency Shelter Locations tab.
- Zoom to Houston.
- Using the same process, remove all the schools within floodplains.
Because these polygons are much smaller than the evacuation zones, you may have to zoom in to individual points to determine if they need to be removed. If any additional information windows appear, close them.
All the schools remaining on the map satisfy the following criteria:
- Must have at least 125 employees
- Must be outside Hurricane Evacuation Zones
- Must not overlap with USA Flood Risk
Your map displays approximately 40 points, which you'll use in the site-selection process. Before saving this result, you'll turn the school points into sites by drawing 2-mile buffers around them. Because site selection uses demographic data to make decisions, you'll enrich these points. Each site will receive the values of the demographic variables within the buffered zone.
- Click the Clear Map button and, in the project pane, turn off the USA Flood Risk (Mature Support) layer.
- Draw a bounding rectangle around the remaining points on the map. In the Selection window, click Create sites for all selected locations.
- On the Rings tab, for Radius, change the first value to 2. Leave the others blank.
- Click Apply to 47 sites. (Your number could vary because of the number of schools you removed from the floodplain as well as the data supporting this lesson is updated periodically.)
The Save Created Sites window opens.
- For Create a new layer, name the layer Schools Outside Flood Zones.
- Click Save.
A new layer is added to your project pane below Point Locations (Sites).
- Close the pop-up.
You've created a project in Business Analyst. You also added data to the map using different methods, including linking ArcGIS Online content, importing a .csv file, and searching by NAICS code. Using this data, you began to narrow down some of the schools in Houston that are potential shelter locations and saved them as sites. The analysis you performed was based on characteristics of the schools' locations. Next, you'll perform a suitability analysis to rank the schools based on the demographics of the populations they'd serve.
Perform a suitability analysis
Previously, you created a project in Business Analyst. Then, you added relevant data to determine what schools in the city of Houston could potentially be suitable hurricane shelters. Next, you'll use the school sites you created in the previous lesson to run a suitability analysis. A suitability analysis applies chosen demographic data to each site using the population inside the buffer rings. First, you'll map the layer of existing hurricane shelters and add data for poverty, population density, income, and age. Then, you'll create weights for each of these variables to determine how much they'll affect the location of your new shelter.
Add demographics variables
Using the school sites you created in the last lesson, you'll add data that will help you determine the suitability of each potential school. First, you'll map existing hurricane shelters to make sure none of the new sites are too close. Then, using the demographic data browser, you'll enrich the school sites with population density, poverty, income, and age data.
- If necessary, sign in to Business Analyst and open your Emergency Shelter Locations project.
- On the ribbon, click Create Maps from Data and choose Suitability Analysis.
The Suitability Analysis pane opens.
- Click Get Started.
There are two options: to add sites from the project or to start with features on the map. This is where the sites saved to the Point Locations layer can be used in future analyses. For now, the points are on the map.
- Click Start with features on the map.
All the selected sites will be displayed.
- Click Next.
- In the Select criteria for your analysis window, click Add criteria and choose Add point layer.
The Add Point Layer window opens.
- Check the Houston Shelters box. Close the Add Point Layer window.
The houston-shelters.csv file is added to the analysis. The location of existing shelters is automatically weighted inversely, or negatively. The closer a potential new shelter site is to existing shelters, the less it will be considered. The preliminary ranked results of the location criteria are shown at the bottom of the screen. Now you'll add demographic criteria.
- Click Add Criteria and choose Add variables from data browser.
The Data Browser window opens. By clicking a variable category, you can add Esri Demographics data to the analysis. You want to find vulnerable populations that will be the most difficult to evacuate. Age is a good indicator; people over the age of 65 are usually not as mobile, whether because of health problems or the loss of a driver's license, for example. Because of this, shelter sites near high populations of the elderly would be more useful.
- In the Data Browser window, click Age.
The Age category opens, showing the three most popular variables associated with age. These variables show mean and median age as well as total population over the age of 18.
- Click Show all ‘Age' Variables.
There are more than 2,400 possible variables to choose from. While these are all helpful variables, you don't need to know the ages of the entire population, just the number of people over 65 years old.
- Click Create a custom variable.
The Create Custom Variable window opens.
- In the Create Custom Variable window, on the Age tab, move the age slider on the left to 65.
Leave the other default settings. The year will automatically be the most current for which data is available, and gender will include both males and females.
- Click Save. In the Save Custom Variable window, click Save.
The new variable is saved to your data browser. It is also added to Selected Variables.
- At the top of the window, click Categories.
You return to the list of categories. The next variable you want to consider in your analysis is poverty. If a family can't afford to evacuate, they may need to go to a shelter.
- Click the arrow on the right. On the second page, locate and click Poverty.
- For Popular Variables, check the box next to 2012-2016 ACS Households Below the Poverty Level. Make sure the percent button is selected.
Percentage is more indicative of a neighborhood's need. The percentage considers the area's poor households in relation to the total population. Like the age variable, Households Below the Poverty Level is added to Selected Variables.
- Click Categories. Add two more variables, making sure that the number sign (#) is selected for both:
- 2018 Total Population (Esri)
- 2018 Median Household Income (Esri)
- Click Selected Variables. Make sure that all four variables are in the menu.
- Click Apply.
The variables open in the Suitability Analysis pane. Because there are five variables, each is automatically assigned an equal weight of 20 percent. Next, you'll change the weights to reflect the relative importance of your criteria.
Weight variables and location
Creating weights for variables allows you to choose certain variables that you want to emphasize more or less in your decision making. Because you're trying to site a shelter that will serve those who are not easily able to evacuate, you'll give age and poverty greater weights. There is also the option to give variables inverse weights, as you did for the current shelter sites. This option makes them count negatively in the suitability analysis.
- In the Suitability Analysis pane, for the 2018 Both Ages 65+ variable, drag the Weight slider up to 25 percent. Click the lock icon.
All the other variables' weights are automatically adjusted. The weights must always add up to 100.
- Change the weight for ACS HHs: Inc Below Poverty Level to 30 percent. Click the lock icon.
- For 2018 Median Household Income (you may have to scroll down to see it), click More Options.
- Next to Influence, choose Inverse. Then, change the weight to 10 percent.
Unlike the other variables, a higher median income indicates less need for a nearby shelter site. People with higher incomes tend to be able to afford to travel farther away during an evacuation. While you'll still include these populations in your analysis, you'll account for the greater need elsewhere.
- Click Filter.
- Change the limit on the left to 0.6 by dragging the bar or by typing that number into the box. (The right limit may change on its own.)
Demographic data is updated periodically. Your results may differ.
- Click OK.
The results of your suitability analysis will have a score of 0.6 or above, where 1 is perfectly consistent with all criteria. Scores are calculated using the percent difference of the value for a given site compared to the target value you selected.
- Click Export and choose Export to a new suitability layer.
- Name the new layer Suitable Shelter Locations.
- Click Export and the new layer is saved to the project.
- On the ribbon, click Emergency Shelter Locations.
The project pane opens.
- Turn off the Houston Shelters layer.
Point to the circles and read the pop-up information. The empty circles represent schools that did not meet your minimum final score of 0.6; the colored circles represent the schools that did. Your final analysis may vary slightly depending on how many schools you converted to sites in the last lesson.
To reopen or edit the suitability analysis later, click the ellipsis next to the layer and choose Open analysis. There, you'll be able to adjust the criteria, weights, and other settings to modify the analysis. If you have previously filtered the results, you'll only be able to see the results of that selection.
In this lesson, you ran a site suitability analysis that identified the top locations for shelters based on need. These sites fit most of the humanitarian requirements for hurricane shelters. Structural compliance will still need to be evaluated, but it is much more feasible to look at the remaining sites than the 900 you started with.
Site selection, with the capability to weight variables both positively and inversely, is a powerful tool that can be used to benefit communities and businesses alike. Depending on what variables you choose to include, you can evaluate everything from insurance ownership to fast food habits.
You can find more lessons in the Learn ArcGIS Lesson Gallery.