Suitability Analysis allows you to identify the most suitable sites from a set of candidates, as defined by applying a set of individually weighted criteria.
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- From the Run Analysis tab, click Suitability Analysis.
- Click Get Started in the Suitability Analysis dialog box.
You can check the Skip this in the future check box to bypass this introduction page and go directly to Suitability Analysis.
To perform Suitability Analysis, you will define your sites, select criteria for your analysis, and view the results.
Define your sites
There are two ways to select the candidate sites to use in your suitability analysis:
- Add sites from project
- Start with features on the map
You may uncheck a selected site to deselect it, and click Prefilter to filter the selected sites based on the values of attributes of the sites; this is useful when you want to run a suitability analysis only on those sites that already meet specific conditions—for example, stores that have a certain minimum number of parking spaces.
You can select a maximum of 5000 sites or features on the map. If you select the Start with Features on Map option, and there are more than 5000 features on the map, you will need to edit the selection to a maximum of 5000 to proceed.
For instance, Sales Volume and City are chosen attributes.
For the numerical Sales Volume attribute, a range of 2,000,000 to 20,000,000 is set as the filter. For the City attribute, all values containing suitability analysis are returned by the search, then selected by clicking Select All.
For a text field, press the space key to see up to 20 unique values. The user entered search string will be highlighted in available options as shown below.
Select criteria for your analysis
Use one or more options to select criteria for your analysis:
- Add variables from data browser
Use the Data Browser to find and add variables.
- Add attributes from sites
Information on how to add attributes for your sites can be found here.
- Add point layer
All layers in the current project that were added using the Business Search and Import File workflows are available. However, layers added using the Web Maps and Layers workflow are available in the Add Point Layer dialog only if they were turned on recently. To add a layer not listed, turn it on in the Project panel by selecting its checkbox and then return to Suitability Analysis.
- Use saved criteria
Use previously saved criteria (a list of variables with weights) from the Saved Criteria List dialog. Move the pointer over a saved list and click Use criteria. Click, to see other options.
The selected criteria will be weighted equally by default, but you can use the sliders to adjust any of the weights. The weights for all your criteria must always add up to 100%. Therefore, if you increase or decrease the weight for any criteria, the weights for each of the remaining criteria will automatically be decreased or increased proportionately. To prevent the weight of any of the criteria from changing in this way, click the lock icon next to it.
Click More options to modify how a variable is used in your analysis.
For variables and site attributes, you can set the Influence, and optionally adjust the Threshold.
Positive Influence is selected by default, which means that the higher the value of the variable, the greater its effect on the final score. Selecting Inverse specifies the opposite: the lower the value, greater is its effect on the score. When Ideal is selected, a value for the Ideal must be selected on the graph that appears with it. The closer the value of the variable to the specified Ideal, the greater its effect on the score will be.
The default Influence for point layers can be changed under Preferences.
Threshold represents the range of values for the variable for the selected sites. In the above image, the 2017 Total Population value for the selected sites ranges from a minimum of 76,131 to a maximum of 342,228. The slider values can optionally be adjusted to exclude sites from your analysis—for example, if the minimum value is set to 95,000 all the sites with a 2017 Total Population value below 95,000 will be excluded from the analysis and will not appear in the Results Table.
For point layers, in addition to the above options, you can also change how the point layer contributes to the analysis.
Count of points is the default, which means that the variable is the number of points from this point layer that fall within a site selected for the analysis.
Summarize layer attribute allows you to choose any attribute from the point layer, in the Weight Field drop-down, and use that as a variable in the suitability analysis by applying the selected Statistic Type to it—for example, When Sales Volume and Sum are selected, the variable will be the sum of the Sales Volume values of all the points from the layer that fall within the site.
When Distance to nearest point is selected, the variable will be the distance from the location of a site to the nearest point from the layer that falls within the site. Straight line distance is the default, and you can change it to Drive distance or Walk distance.
- When Drive distance or Walk distance is selected, the calculation will consume credits.
- When a point layer is one of the selected criteria, and at least one of the selected sites has a large area, the suitability analysis may take a few moments to process.
- When Walk distance is selected, the walk distance between a site selected for suitability analysis and a location in the point layer cannot exceed 50 miles. If this condition is not met, the analysis will return an error, and you must select a different Distance type or modify your point layer accordingly.
- When Drive distance or Walk distance is selected, depending on the number of sites and number of points in the point layer, the calculation can take up to a few minutes. The wait time will be shown while the calculation is in progress.
When finished selecting and modifying your criteria, view the Suitability Analysis Results table on the right for a list of your sites ordered by final score. The selected sites are also color coded by score on the map.
- Hover the pointer over an item in the table and the corresponding site is highlighted on the map.
- Double click on any row in the table to zoom in to the corresponding site on the map.
- Click on any column header to sort the table by the data in that column.
- Use the options under Refine results to show locations only, filter by score, and change the color ramp. Click Export to export the results of your analysis.
- To learn how the scores are calculated, see the Step-by-step guide.
By default, your selected sites are shown on the map, color-coded by score. You can set the Show locations only toggle switch to view the site locations only—without the rings, drive times, or walk times. In this mode, the site locations are numbered by their rank in the Suitability Analysis Results table.
You can filter the view of the analysis for the sites you have chosen. This allows you to highlight sites that meet a certain score visually on the map. For example, when viewing the population by age in a block group, you can create a filter by selecting greater than and entering a value of 5,000. The map will only show color-shaded block groups where the population by age is more than 5,000 people.
To filter your analysis you will perform the following steps:
- Click the Filter by score icon.
- Move the sliders to filter the map.
- Click Ok.
The Colors drop-down menu allows you to select from a palette of colors for coding the results of your analysis on the map and in the results table.
- To change the colors, click the Colors drop-down menu and the color choices appear.
- Click the color you want to view in your map.
You can export the results of your analysis to an Excel file, or to a new suitability layer.
- Click Export in the Suitability Analysis panel.
The Export dialog will appear.
- Choose your export format: Excel file, or a new suitability layer.
- Click Export.
If you choose to export as a new suitability layer, the results will be saved under the Other Layers section of your project. Click and click Open analysis to reopen the analysis and modify it. If the sites for your suitability analysis were created from a point or polygon layer, they will be saved to the project as a new site layer.
If any of the sites in this site layer are deleted, the saved suitability layer will not open, and will return an error message.
Use Suitability Analysis to rank and score sites based on multiple weighted criteria. Suitability can be ranked based on data variables from Esri’s ArcGIS Living Atlas of Demographic and Socioeconomic data and your site attributes. Once you select your criteria, you can assign weights to them, get weighted scores for each potential site, and review their final score ranks from most suitable to least suitable site. Suitability Analysis can be run on a set of point location sites, polygon areas, standard geographies, or any combination thereof.
The following guide will lead you through an example of how to execute this workflow.
From the Run Analysis tab click Suitability Analysis.
You will see the Introductory screen that gives you a very brief overview of the Suitability Analysis workflow. If you do not wish to see this screen every time, select Skip this in the future, before you click Get Started.
For the purposes of this example, you are a real estate agent who has taken on a new client interested in buying a home. Your client is a young professional with an advanced degree, and has an elderly parent living with him who relies on being in close proximity to a senior center for socializing and leisure activities. Your client wishes to buy a home to reside in, that is within walking distance to one of his preferred senior centers, so that his parent has convenient access. You need to present him with a neighborhood analysis for these senior center locations, to help evaluate their suitability based on his criteria:
- Greater number of individuals with advanced degrees
- Lower median home value, which would indicate greater affordability of purchasing a home
- A median age of the population close to his own age (39)
To begin the Suitability Analysis workflow you will select the sites that you want to use in the analysis. For this walkthrough, five sites were already loaded on the map, each representing an area 0.75-mile radius around a senior center.
- Click Start with Features on Map. Alternatively, we could click Add Sites from Project, to add sites not already on the map.
The resultant map with your five sites is shown.
- Click Next.
- Expand the Add Criteria drop-down list and select Add variables from data browser.
You will select variables using the Data Browser.
- Select the following three variables and click Apply.
After selecting your criteria the sites are automatically scored. By default, all three variables are weighted equally and Influence is set to Positive.
- 2020 Pop Age 25+: Grad/Professional Degree
- 2020 Median Home Value
- 2020 Median Age
- Refine the criteria results with the following:
- You want a site to score higher if it has greater number of individuals holding Grad/Professional degrees, so you will keep the Influence setting Positive for that variable.
- For Median Home Value, a lower value is more desirable as it is indicative of greater home affordability. Therefore, you will change the Influence setting to Inverse.
- For the Median Age, the closer the value is to 39 the more ideal the site. Therefore, you set the Influence to Ideal. Use the slider to specify the ideal value of 39.
You may also adjust the thresholds to exclude sites from the Results table that do not meet must-have criteria for a variable— for example, you may set a maximum value of $600,000 for Median home value so sites that have a median home value above $600,000 are excluded. Because you are not scoring too many sites in this example, you will not adjust the threshold values and keep the default setting to include their full range.
The color ramp is applied to color-code the sites on the map by their final score.Whenever you modify the settings for any of the criteria, the Suitability Analysis Results table gets updated to show the sites ranked by the updated criteria. With the above settings, Candidate 2 receives the highest final score in the Results Table.
- Assign a Weight of 60% to 2020 Median Home Value. You want to do this as home affordability is a much higher priority for your client over his other preferred criteria and it will be a better use of his time to look for a home in the vicinity of those senior centers where home prices are lower.
Assigning weight to one variable will proportionately reduce the weights to the other variables. In this case 2020 Pop Age 25+: Grad/Professional Degree and 2020 Median Age have been reduced to 20% each, as the weights must always add up to 100%.
Using the above weight adjustment - the site, Candidate 1, receives the highest score in the Suitability Analysis Results table.
Further details regarding how the below scores are calculated can be found in this section.
- To show sites that meet a certain minimum score, click the Filter by score icon . In this case, only those sites with a score > 0.5 will be shown.
- Drag the slider for the lower limit from 0 to 0.5 (or type the value 0.5 in the text box).
As we see above, the Suitability Analysis Results table is filtered accordingly to show only those sites that have a final score > 0.5. You may click Export to export the results to an Excel file, or to a new suitability layer. When the suitability layer is open on the map, you can share it with others in your organization using the Share Map tool.
Weighted score calculations
The following are details regarding how the above scores are calculated, using some of the values in the annotated table above to illustrate. Each weighted score is calculated as a percent difference of the value for a given site compared to the target value selected by the user. Here, GP stands for the Grad/Professional Degree variable, HV stands for the Median Home Value variable and MA stands for the Median Age variable.
As the above table illustrates, Candidate 1 site has the highest suitability score of 0.89 (Cell 1A). This score is calculated by adding the weighted scores for each of the three variables (GP, HV, MA) used in the analysis.
- First, we will examine how the number of households with graduate degrees (GP) contributed to this score.
- Site Candidate 1 has 1046 households with Grad/Professional Degree (Cell 1B).
- The maximum value for GP across all the sites is 1318 households for the site Candidate 2 (Cell 2B).
- Similarly, the smallest value for GP across all the sites is 826 households for site Candidate 5 (Cell 5B).
In this example, the greater number of people with graduate degrees is desired. This is a positive relationship, so these values are plugged into this formula to calculate the score for GP for Candidate 1:
We can calculate what the score is for GP for Candidate 1 using the values outlined above:
This means, that Candidate 1 has a score of 0.45 (Cell 1C). Once the score is calculated, the weight is then applied to the value to determine how much GP will contribute to the total suitability score for the site. In our example, a weight of 20% was applied to GP. Therefore, the weighted score for GP is calculated as 0.09 (Cell 1D):
0.20*0.45 = 0.09
The whole weighted score calculation for Candidate 1 can be expressed as:
abs is the absolute value function.
- Next, let us see how the Median Home Value of the site (HV) contributed to the score:
- The homes within the area of site Candidate 1 have a Median Home Value of $390,062 (Cell 1E).
- The maximum value for HV across all the sites is $639,400 for the site Candidate 5 (Cell 5E).
- Similarly, the smallest value for HV across all the sites is $390,062 for site Candidate 1 (Cell 1E).
Here, a lower Median Home Value is desired, as an indicator of better affordability. This is an inverse or negative relationship, so these values are plugged into this formula to calculate the score for GP for Candidate 1:
We can calculate what the score is for HV for Candidate 3 using the values outlined above:
This means, that Candidate 1 has a score of 1 (Cell 1F). Once the score is calculated, the weight is then applied to the value to determine how much HV will contribute to the total suitability score for the site. In our example, a weight of 60% was applied to HV. Therefore, the weighted score for GP is calculated as 0.60 (Cell 1G):
0.60*1 = 0.60
The whole weighted score calculation for Candidate 1 can be expressed as:
- Lastly, let us examine how the Median Age of the people living in the area (MA) contributed to the score:
- The population living in the area of site Candidate 1 has a Median Age of 39.1 (Cell 1H).
- The maximum value for MA across all the sites is 53.1 for the site Candidate 5 (Cell 5H).
- The minimum value for MA across all sites is 31.2 for the site Candidate 3 (Cell 4H).
Here, an ideal value of 39 was selected, as a median age closer to 39 is more desirable. These values are plugged into this formula to calculate the score for MA for Candidate 1:
This means, that Candidate 1 has a score of 0.99 (Cell 1I). Once the score is calculated, the weight is then applied to the value to determine how much MA will contribute to the total suitability score for the site. In our example, a weight of 20% was applied to MA. Therefore, the weighted score for MA is calculated as 0.20 (Cell 1J):
0.20*0.99 = 0.20
In this example we have not adjusted the threshold for any of the variables. If, for example, the threshold had been set such that the GP value for Candidate 1 did not fall within the specified range, then the weight for that variable would default to 0 and effectively GP wouldn’t be used in the final score calculation - filtering would be applied and that particular suitability score would not be used in the final results table.
Final score is calculated as:
The final score that you see in the table may be slightly lower due to rounded values.
This walkthrough gave you a basic understanding of how Suitability Analysis works. You were able to create a ranked list of the top 3 most suitable senior centers in the area, for your client's weighted criteria from the point of view of house hunting.
You may add additional sites and variables, and further adjust the settings to perform an even more sophisticated suitability analyses. You could further enhance your analysis by including relevant variables that are attributes of the sites being scored. For example, every senior center may have a rating, which is an indicator of quality. You may want to factor that into your analysis, with the Add attributes from sites option under Add Criteria.