Assess parcel suitability

The suitability tool allows you to select parcels that are suitable for further development. For example, you can use the tool to find optimal sites for housing, a school, or open space. The suitability of each parcel is assessed based on its properties, which are called criteria. Criteria can be properties such as the underlying zoning type, the maximum building height, or the age of existing buildings on the parcel. You can use prepopulated parcel and zoning properties and custom external layers as criteria. By reclassifying the original values of each criterion to a common scale and giving a weight to each criterion, a suitability score is calculated using a weighted sum. After the calculation, you can identify and select suitable parcels on the map. All settings are stored in a suitability model. You can have multiple suitability models in your plan.

There are five main steps when assessing parcel suitability:

1. Create a suitability model.
2. Add criteria data.
3. Reclassify the original values of each criterion to a common suitability scale between 0 and 10 (0 is unsuitable; 10 is most suitable).
4. Weight criteria relative to one another and combine them to calculate a suitability score for each parcel inside the study area.
5. Select suitable parcels.

Open the suitability tool

To open the suitability tool, complete the following steps:

1. Open the plan editor.
2. Click Development in the header.

   Ensure that the side panel on the right is expanded and is in development mode. To show or hide the side panel, click the expand button.

3. Click the Parcel suitability button on the workflow toolbar at the right of the view.

   The suitability tool opens.

Manage suitability models

Manage your suitability models in the Suitability model section of the Suitability tool side panel. Choose from the following options:

• Create a suitability model
• Copy a suitability model
• Edit the name of a suitability model
• Delete a suitability model

Create a suitability model

To create a suitability model, complete the following steps.

Note:

If there is no suitability model in your plan, a new one is automatically created when opening the suitability tool.

1. Open the suitability tool.
2. Click the Options button next to the suitability model drop-down list in the side panel and select New suitability model.

   A new suitability model is created. See Add criteria to learn how to configure suitability model criteria.

   Note:

   To change the name of the model, click the Options button next to the suitability model drop-down list and select Edit name. Edit the name and press Enter to confirm.

Copy a suitability model

To copy a suitability model, complete the following steps:

1. Open the suitability tool.
2. Select the suitability model you want to copy from the drop-down list in the side panel.
3. Click the Options button next to the suitability model drop-down list and select Create copy.

   A copy of the suitability model is created.

   Note:

   To change the name of the model, click the Options button next to the suitability model drop-down list and select Edit name. Edit the name and press Enter to confirm.

Edit the name of a suitability model

Complete the following steps to edit the name of a suitability model:

1. Open the suitability tool.
2. Select the suitability model you want to rename from the drop-down list in the side panel.
3. Click the Options button next to the suitability model drop-down list and select Edit name.

   The suitability model name field is focused.

4. Edit the name and press Enter to confirm.

Delete a suitability model

To delete a suitability model and its criteria, complete the following steps:

1. Open the suitability tool.
2. Select the suitability model you want to edit from the drop-down list in the side panel.
3. Click the Options button next to the suitability model drop-down list and select Delete.

   A pop-up appears.

4. Click Delete to confirm that you want to delete the suitability model.

Add criteria

There are three types of criteria based on the source:

• Parcel—Includes prepopulated parcel properties such as parcel area
• Zoning—Includes prepopulated zoning properties such as zoning type or allowed building height
• External layer—Allows you to select an external feature layer as a source

Add criteria from parcel or zoning property

To add a criterion from a parcel or zoning property, complete the following steps:

1. Open the suitability tool.
2. Select the suitability model you want to edit from the drop-down list in the side panel.
3. Click the Add criteria button in the side panel.

   The Add criteria panel appears.

4. Provide a name for the criterion.
5. Select Parcel or Zoning as a source.

   The Field section appears with a drop-down list.

6. From the drop-down list, select the field you want to use.
7. Click OK to add the criterion.

   The Edit criteria panel appears. See the Reclassify criteria section below for more information.

Add criteria from an external layer

To add criteria from an external layer property, complete the following steps:

1. Open the suitability tool.
2. Select the suitability model you want to edit from the drop-down list in the side panel.
3. Click the Add criteria button in the side panel.

   The Add criteria panel appears.

4. Provide a name for the criterion.
5. Select External layer as a source.

   The External layer section appears.

6. Click the Select item button to open the Select external layers dialog box.
7. Select the layer you want to use and click Select.

   You can use polygon, polyline, or point feature layers. Feature layers with multiple sublayers are not supported.

   Additional options are enabled and appear below the portal item picker.

8. Select the field you want to use from the Field drop-down list.
9. Choose the method you want to use to spatially join external features with parcels:
   • Parcel—External features are joined if they intersect the parcel geometry.
   • Parcel centroid—External features are joined if they intersect the parcel's centroid.

   You can only select Parcel for polyline and point layer types.

10. If multiple features are intersecting a parcel, select the method you want to use to combine multiple records:
    • Any—A random feature is selected.
    • Sum—Values are summarized.
    • Average—Values are averaged.
    • Minimum—The minimum value is selected.
    • Maximum—The maximum value is selected.

    If the source field contains text, you can only select Any.

11. Click OK to add the criterion.

    The Edit criteria panel appears. See the Reclassify criteria section below for more information.

Note:

Keep the following in mind:

• Ensure that you share the layers used in the suitability model if the plan is shared with others. You can do this on ArcGIS Online. Criteria with an inaccessible layer (either not shared or deleted) are highlighted with a label and excluded from the analysis.
• You can click the link to the feature layer on ArcGIS Online as well as see other source settings in the Edit criteria panel.

Reclassify criteria

The original criteria values need to be reclassified to a common suitability scale between 0 and 10. The reclassification depends on the type of source values:

• Numeric values—Values are reclassified based on numeric intervals.
• Discrete values—Individual values are reclassified.

You can reclassify the original criteria values in the Edit criteria section of the suitability tool. Alternatively, you can also use numeric values from external layers without reclassification. In this case, the values are used directly as scores.

Reclassify numeric criteria

Numeric values are reclassified based on intervals. All source values within the interval will be reclassified. The start of the range is inclusive, and the end of the range is exclusive (start ≤ source value < end). For example, if the range starts at 0 and ends at 100, 0 is reclassified, but 100 is not.

To reclassify numeric criteria, complete the following steps:

1. Open the suitability tool.
2. Select the suitability model you want to edit from the drop-down list in the side panel.

   The criteria list appears. If it is empty, see Add criteria to learn how to add criteria.

3. Click the name of a criterion with numeric source values.

   The Edit criteria panel appears. Alternatively, the Edit criteria panel automatically appears after adding a criterion.

4. Check the Apply reclassification check box if you are using an external layer.
5. Click the Add interval button in the Intervals section to add an interval.
6. Provide start and end values for the interval.

   Setting the start value of an interval automatically sets the same value for the end of the preceding interval.

7. Do one of the following to reclassify the source values that fall within the interval:
   • Assign a score to all source values that fall within the interval (this is most common)—Provide a score between 0 and 10 and check the Score check box. This score is used in the weighted sum when combining multiple criteria.
   • Always deem parcels with source values that fall within the interval unsuitable—Uncheck the Score check box. Parcels with matching values are always assigned a final score of 0, ignoring scores of other criteria in the weighted sum. In this case, the Score value is ignored. You can use this to exclude restricted areas from your analysis.
8. Optionally, add more intervals by doing one of the following:
   • Add an interval at the bottom—Click the Add interval button at the end of the list of intervals.
   • Add an interval above an existing interval—Click the number to the left of the interval and click Add above.
   • Add an interval below an existing interval—Click the number to the left of the interval and click Add below.
9. Optionally, reclassify parcels with a source value of NULL or without intersecting source features. Click the Add value button in the Other Values section and assign a score.

   No value or no intersection automatically shows as a source.

10. Click OK to finish the reclassification.

    The list with all criteria appears.

Note:

Keep the following in mind:

• To remove an interval, click the number to the left of the interval and click Remove.
• Intervals cannot have the same start and end value. The end value must be higher than the start value.
• Parcels with values that are outside of the interval are not assigned a suitability score, independent of other criteria. To avoid this, ensure that the interval includes all source values.
• Parcels without intersection or with a source value of NULL are not assigned a suitability score. To avoid this, add No value or no intersection as a source value and assign a score (see above).

Reclassify discrete criteria

For criteria with discrete values, individual values are reclassified. In this process, a source value is assigned to a score.

To reclassify discrete criteria values, complete the following steps:

1. Open the suitability tool.
2. Select the suitability model you want to edit from the drop-down list in the side panel.

   The criteria list appears. If it is empty, see Add criteria to learn how to add criteria.

3. Click the name of a criterion with discrete source values.

   The Edit criteria panel appears. If you just added a criterion, the Edit criteria panel automatically appears.

4. Click the Add value button in the Values section to add a value.

   A drop-down list including all source values appears.

5. From the drop-down list, select the value you want to use.
6. Do one of the following to reclassify the source value:
   • Assign a score to the source value (this is most common)—Provide a score between 0 and 10 and check the Score check box. This score is used in the weighted sum when combining multiple criteria.
   • Always deem parcels with matching values unsuitable—Uncheck the Score check box. Parcels with matching values are always assigned a final score of 0, ignoring scores of other criteria in the weighted sum. In this case, the Score value is ignored. You can use this to exclude restricted areas from your analysis.
7. Optionally, do one of the following to add more intervals:
   • Add a value at the bottom—Click the Add value button at the end of the list of values.
   • Add a value above an existing value—Click the number to the left of the value and click Add above.
   • Add a value below an existing value—Click the number to the left of the value and click Add below.
8. Optionally, reclassify parcels with a source value of NULL or without intersecting source features. Add a value, select No value or no intersection from the drop-down list, and assign a score.
9. Click OK to finish the reclassification.

   The list with all criteria appears.

Note:

• To remove a value, click the number to the left of the value and click Remove.
• Parcels with values that have not been reclassified are not assigned a suitability score, independent of other criteria. To avoid this, ensure that you add all source values to the reclassification list.
• Parcels without intersection or with a source value of NULL are not assigned a suitability score. To avoid this, add No value or no intersection as a source value and assign a score (see above).

Use an external layer without reclassification

You can use criteria values from an external layer without reclassification. This is useful if you calculated the suitability scores in another application. To do so, complete the steps below.

Note:

Keep the following in mind:

• The scores must be stored in a numeric field.
• Field values will be clipped between 0 and 10. Be sure that your values fall within this range or are set to -1 (see below).
• A value of -1 will exclude the parcel from the analysis.

1. Open the suitability tool.
2. Select the suitability model you want to edit from the drop-down list in the side panel.

   The criteria list appears. If it is empty, see Add criteria to learn how to add criteria.

3. Click the name of a criterion with numeric source values.

   The Edit criteria panel appears. If you just added a criterion, the Edit criteria panel automatically appears.

4. Uncheck the Apply reclassification check box in the Reclassification section.
5. Click OK.

   The list with all criteria appears.

Weight criteria

Multiple criteria are combined through a weighted sum. You can weight the criteria relative to each other to reflect differences in their importance. Weights can have any value greater than or equal to 0. During the calculation process, weights are normalized. The normalized weight is reflected in the percentage values in the criteria list, which always sum up to 100 percent. The cumulative suitability score for each parcel is between 0 and 10.

To weight criteria, complete the following steps:

1. Open the suitability tool.
2. Select the suitability model you want to edit from the drop-down list in the side panel.

   The criteria list appears.

3. Do one of the following to change the weight value:
   • Change the absolute weight value—Change the value in the Weight field. The relative weight (%) automatically changes accordingly.
   • Change the relative weight (%)—Adjust the percentage slider. The absolute weight value automatically changes accordingly.

   Changing the weight of one criterion adjusts its relative importance to all other criteria. This is reflected in a change of the percentage values of all other criteria.

4. Optionally, exclude criteria from the calculation by unchecking the check box next to the criteria name.

   Unchecked criteria will not be used in the calculation. This is useful when you want to quickly test the effect of certain criteria on the final result.

Note:

Click Weight to reset all weights to 1.

Edit criteria

You can edit the name of a criterion or delete the criterion.

Edit criteria name

To edit the name of a criterion, complete the following steps:

1. Open the suitability tool.
2. Select the suitability model you want to edit from the drop-down list in the side panel.

   The criteria list appears.

3. Click the name of the criterion you want to edit.

   The Edit criteria panel appears.

4. Edit the name of the criterion.
5. Click OK.

Delete criteria

To delete a criterion, complete the following steps:

1. Open the suitability tool.
2. Select the suitability model you want to edit from the drop-down list in the side panel.

   The criteria list appears.

3. Click the name of the criterion you want to delete.

   The Edit criteria panel appears.

4. Click the Delete button .

   The criterion is deleted.

Calculate and explore scores

To calculate the suitability score for each parcel, complete the following steps:

1. Open the suitability tool.
2. Select the suitability model for which you want to calculate the scores from the drop-down list in the side panel.
3. Select the scenario for which you want to calculate the scores using the scenario switcher.
4. Click Calculate scores below the list of criteria.

   The suitability score for each parcel inside the study area is calculated and the map shows the result. Suitable parcels are colored in green, and unsuitable parcels are in red. Parcels that have been excluded from the analysis are colored in gray. When you click a parcel, a pop-up shows detailed information about the cumulative score as well as the scores and values of each criterion.

Note:

• Parcels with values that have not been reclassified are not assigned a suitability score and are not colored. Be sure to reclassify all values to avoid this. You can identify the criteria with incomplete reclassifications in the parcel pop-up.
• You can compare the suitability result of different scenarios using the scenario switcher. The scores need to be calculated for each scenario individually.
• The scores of the last used suitability model are stored while you edit the current plan.
• You can visualize the result of the last calculated suitability model outside the suitability tool. See Visualize the parcel suitability layer to learn more.
• You can export the suitability result to a web scene. See Create a scenario web scene to learn more.
• The suitability score is only calculated for parcels inside the study area. See Edit the study area to learn how to modify the study area.

Select suitable parcels

After suitability is calculated, you can select parcels based on their suitability score. To do this, complete the following steps:

1. Open the suitability tool.
2. Select the suitability model you want to use from the drop-down list in the side panel.

   In the map view, a blue header with a slider appears. If the slider is missing, no suitability score was found. You need to calculate a score first.

3. Do one of the following to select suitable parcels:
   • Adjust the blue slider.
   • Set a score in the input field next to the slider.

   All parcels with a score equal to or above the defined threshold are selected.

4. Click Done in the blue header.

   The suitability tool closes. The parcels remain selected and a parcel suitability layer is added to the layers listed in the menu button options.

Display the parcel suitability layer

You can display the parcel suitability layer of the last calculated suitability model outside the suitability tool. To enable the parcel suitability layer, complete the following steps:

1. Click the menu button at the upper left of the header.

   The side panel expands.

2. Click the layer named after the last calculated suitability model inside the Parcel suitability section of the side panel.

   The parcel suitability layer is shown in the scene.

Note:

• You can switch scenarios to compare the suitability results of different scenarios. The scores need to be calculated for each scenario individually. Use the parcel suitability tool if the scores are missing.
• Urban only keeps the suitability layer of the last used suitability model.
• The suitability layer is not persisted. If you exit the plan, the scores need to be calculated again. Consider exporting the scenario to a web scene to persist the result. See Create a scenario web scene to learn more.