Review maps

To verify that a map and the layers within it are optimized to support high usage levels, run the Review map tool . This tool compares the web map configurations to known best practices for supporting high-traffic maps and provides a report verifying where best practices are already applied and, if needed, where they can be added. This promotes efficient use of your organization’s resources and gives map authors confidence that their web map is aligned with best practices for supporting increasing demand.

Note:

The Review map tool is available when the web map contains hosted feature layers and tables. Support for other layer types will be available in a future release of Map Viewer.

Review a map

To evaluate map scalability, complete the following steps:

1. Sign in to your organization.

   You must be the web map owner or a member of the default administrator role, member of a custom role assigned the set of privileges to manage all content owned by organization members, or a member of a shared update group with which the web map is shared.

2. In Map Viewer, open the map you want to review.
3. On the Contents (dark) toolbar, click Review map .
4. In the Review map pane, click Expand to view the layers in each recommendation area, and click Manage configuration to open the relevant item setting or configuration.

   Note:

   If you do not have permission to make a change to a configuration, click Learn more to open the documentation for the setting or configuration.

5. Optionally, click Advanced review , answer the prompts, and click Refine recommendations to refine the recommendations based on the intended map use.

   Note:

   Prompt responses are only stored as long as the Review map pane is open. If you move to another pane, refresh the page, or exit Map Viewer, you will have to answer the prompts again.

6. Optionally, click Summary , and review the Map and Layers sections to learn more about the map contents and features present in the map layers.
7. Click Review map , and click Refresh to refresh the list of recommendations after making changes to the layers in the map.
8. Repeat steps 4 through 7 as needed.

Understand map recommendations

When you run the Review map tool , the Review map pane opens with a list of best practices confirming which are applied and where there may be additional optimizations to consider.

There are five types of recommendations listed in the Review map pane, in order of priority:

• High priority —The map has a configuration that is likely to cause significant performance degradation or rendering failures for end users. These issues should be resolved before sharing the map.
• Moderate priority —The map has a configuration that may impact draw performance or scalability, particularly at scale or under high traffic. Resolving these issues is recommended.
• Low priority —The map has a configuration that could be optimized for better performance. These issues are unlikely to cause noticeable problems but are worth addressing when possible.
• Information —Diagnostic or contextual details about the map's configuration are provided. No action is required, but the information may be useful when troubleshooting or optimizing the map.
• No recommendations needed —No action is required.

The tool currently checks hosted feature layers in a web map for the following:

• Attribute index
• Cache control
• Complex geometries
• Pop-up configuration
• Publicly editable layer
• Refresh interval
• Relative date condition
• Reprojection
• Spatial index
• Visibility range

Each area describes a configuration with direct impact on scalability and, where needed, provides recommended actions to make the map more scalable.

Attribute index

Adding an attribute index to fields referenced by filters or definitions searching for specific words or phrases in a string field may improve query performance.

Cache control

Increasing the maximum cache age setting decreases the frequency with which the browser and content delivery network (CDN) check for changes. This reduces the overall demand for organization resources.

Complex geometries

Simplifying complex features by reducing the number of vertexes results in faster processing, which can improve drawing performance. This can be achieved using any of the following tools:

• Optimize drawing of complex lines and polygons on the Settings tab of the layer's item page
• ArcGIS Pro geoprocessing tools such as Dice, Multipart To Singlepart, and Simplify Polygon

Feature layers with complex geometries can also be published as tile layers, which support fast visualization of large datasets using a collection of predrawn raster tiles or vector tiles.

Pop-up configuration

The FeatureSetByPortalItem ArcGIS Arcade function represents a connection to a set of features in memory or in a server. This is an effective way of combining data from multiple sources into a single FeatureSet, but it may slow pop-up responsiveness.

Publicly editable layer

Layers with editing enabled cannot use CDN caching, which means they may not scale efficiently enough to support high volume demand. Hosted feature layer views are a common way to ensure scalability while also allowing authorized users to edit and maintain the data.

Refresh interval

A refresh interval keeps maps in sync with the latest data while the map is open. However, a more frequent refresh interval results in higher resource usage, so it should be set to the most infrequent interval required for the intended audience.

Relative date condition

In some apps, layers with relative date conditions enabled cannot use CDN caching. This means they may not scale efficiently enough to support high volume demand. Relative date conditions can be reconstructed to use fixed dates in Date, Date only, or Time only fields.

Reprojection

When a layer's spatial reference does not match the map's spatial reference, data must be reprojected in real time with each map operation. This can unnecessarily slow map responsiveness. If this occurs, you can change the map or the layer projection to match the desired spatial reference, which is typically set by the basemap. You can adjust these map and layer settings in ArcGIS Pro using the Project (Data Management) tool or by setting the map properties.

Spatial index

Spatial indexes improve the performance of spatial queries, such as drawing features on a map or searching for features. Generally, if the layer is drawing slowly, it may be due to features having been added beyond the layer's extent after the spatial index was originally created. You can rebuild the spatial index to ensure that it is optimized for the data in its current state.

Visibility range

Specifying the zoom level at which content is drawn is known as setting the visible range. Because most data does not need to be shown across all zoom levels, you can reduce unnecessary resource usage by adjusting the visible range for each layer in the map.