Enable synchronization on feature layers (feature services) to allow you and others in your organization to work with the layers even when you don't have network connectivity.
Enabling sync allows clients to work with a local copy of the data. If the publisher chooses to allow it, clients can edit the local copy of the data and synchronize with the feature service when connectivity is available.
Offline ArcGIS Server feature services
Before you enable sync on an ArcGIS Server feature service, the data in the service must meet specific requirements, and those requirements vary depending on how the data will be used when taken offline.
See Prepare data for use in offline feature services in the ArcGIS Pro help for information about what type of data can be used in an offline ArcGIS Server feature service.
When you publish a feature service with sync enabled or you enable sync on the feature service in ArcGIS Server Manager, a feature service replica is created.
The operations you define on the feature service determine how the feature service can be used. There are two configurations supported for feature services that participate in offline map use:
- Read-only data—If clients will only query the data they download from the feature service to use while offline, set the Query and Sync capabilities on the feature service. With this configuration, the data cannot be edited while offline and synchronized back to the service.
To set the equivalent operations when you publish from ArcGIS Pro, disable editing but enable sync. See Configure a web feature layer in the ArcGIS Pro help for more information.
- Editable data—If clients will edit the data when offline and synchronize changes with the feature service when they have connectivity, set the following on the feature service:
- Any combination of Create, Delete, and Update
To set the equivalent operations when you publish from ArcGIS Pro, enable editing, choose what type of edits are allowed, and enable sync. See Configure a web feature layer in the ArcGIS Pro help for more information.
- If the map includes attribute rule error layers and you enable sync on the ArcGIS Server feature service, do not edit these error layers in the offline map. If you do, the edits will not be applied to the error layers when you synchronize.
For feature services on stand-alone ArcGIS Server sites, allowed operations apply only to publishers and users. Server administrators and the service owner have full access to the service with all operations allowed.
As a result, data that is taken offline by an administrator or the service owner is always editable. If you require read-only offline feature layers, they must be taken offline by a nonadministrative user other than the feature service owner.
For feature services on federated ArcGIS Server sites, organization owners and feature layer owners can edit a feature layer even if the feature layer does not have editing enabled. The allowed editing operations set on a feature service on a federated site apply to the following:
- Any user who is a member of a role that has privileges to edit features and who has access to the feature layer.
- If you share the feature layer with everyone (public), anyone with access to the feature layer can edit it. This includes people not signed in to the organization and all organization members, even those who do not have privileges to edit features.
When you enable sync on the feature service when publishing to the active portal's federated server in ArcGIS Pro, you have additional options when the data is registered as versioned. See Configure a web feature layer in the ArcGIS Pro help for information on these options.
Once the feature service exists, publishers and administrators can disable the sync capability in ArcGIS Server Manager. For example, a publisher or administrator can disable the sync capability on the service to prevent clients from synchronizing with the service while data maintenance tasks are in progress, such as rebuilding indexes.
Do not disable sync if any offline maps exist that contain the sync-enabled feature service or if the feature service has been shared in a distributed collaboration.
Change sync options for ArcGIS Server feature services
When a read-only ArcGIS Server feature service (only query and sync are enabled) contains versioned data, no replica version is created when you take the data offline. When a client synchronizes with the published version, changes to the published feature service are automatically available in the client.
If the ArcGIS Server feature service is editable, sync options and behavior vary depending on whether the data in your service is registered for traditional versioning, registered for branch versioning, or enabled for archiving and not registered for versioning. See Prepare data for use in offline feature services in the ArcGIS Pro help for descriptions of these options.
For examples of offline versioned data scenarios, see the following:
Publishers and administrators can alter the sync options in ArcGIS Server Manager. However, do not change sync options if any offline maps exist that contain the sync-enabled feature service or if the feature service is shared in a distributed collaboration.
If the feature service is not in use offline or in a distributed collaboration, follow these steps to change the sync option on a feature service that contains versioned data:
- Sign in to ArcGIS Server Manager as the service owner or ArcGIS Server administrator.
- Ensure Services is selected at the top of ArcGIS Server Manager.
- Browse to the feature service and click the service's name to open information about that service.
- Click Capabilities.
- Select Feature Access.
- Under Properties, click Advanced Options.
The Feature Service Advanced Options dialog box appears.
- Under Sync, change the version creation options.
- Click OK to close the Feature Service Advanced Options dialog box.
- Click Save and Restart to apply the setting changes to the feature service.
The service is unavailable while it is restarting.
Geometry updates and true curves
You can configure ArcGIS Server feature services to allow geometry updates and edits to data with true curves. These settings are enforced when edits are synchronized from the client to the service. Any edits the client made that violate the geometry updates and true curve settings of the feature service will not be synchronized with the service.
Not all offline clients support true curves.
Output from downloading local copies of the data or synchronizing with the service
When you download data to a local client, a file that contains the data is created in the ArcGIS Server output directory, and your client downloads that file. By default, any files that have not been accessed by any process for more than 10 minutes are removed from the output directory. If you expect more than 10 minutes will elapse before the client starts downloading the file, you can create another output directory with a longer cleanup time and use this output directory for your feature services. Alternatively, you can increase the cleanup time of the default output directory; however, this affects all services using the default output directory.
When you use the createReplica operation to create a local copy of the data, you choose the layers, tables, and extent of the data to copy. By default, the local copy includes features that intersect the extent and rows in tables related to these features. For tables, you can choose to apply a query filter or include all rows instead of using the default. When you copy a large amount of data and have many relationship classes, setting a filter or all rows for the tables may improve performance. To set a filter or include all rows, see the layerQueries parameter of the createReplica operation in the ArcGIS REST API help.
Synchronous and asynchronous modes
The sync operations that download local copies of the data or synchronize changes to the service can be run in synchronous or asynchronous mode. When using synchronous mode, the processing is done by the service; therefore, service settings such as the minimum and maximum number of instances used, timeout intervals, and recycling intervals apply. When using the asynchronous mode, the processing is done by the SyncTools geoprocessing service that comes preconfigured with ArcGIS Server; therefore, the settings for the SyncTools geoprocessing service apply.
Hosted feature services
If you publish feature services hosted on ArcGIS Online or an ArcGIS Enterprise portal, the data is always nonversioned and is automatically prepared for offline use when you enable sync.
See instructions for enabling sync for the type of hosted feature layer you will include in an offline map:
The editor settings you enable on the hosted feature layer determine what offline users can do with the data.
- Read-only data—If clients will only query the data they download from the hosted feature layer to use while offline, enable sync but do not enable editing on the hosted feature layer item. With this configuration, the data cannot be edited while offline and synchronized back to the feature layer.
You can also disable editing but enable sync when you publish from ArcGIS Pro. See Configure a web feature layer in the ArcGIS Pro help for more information.
- Editable data—If clients will edit the data when offline and synchronize changes with the hosted feature layer when they have connectivity, allow editing, choose what type of edits are allowed, and enable sync on the hosted feature layer item.
You can set the equivalent options when you publish from ArcGIS Pro. See Configure a web feature layer in the ArcGIS Pro help for more information.
Editor tracking, ownership-based access control, and offline data
You can track who edits the data while offline. You can also control what features editors see or can edit based on who created the feature. This applies to ArcGIS Server feature services and hosted feature layers.
To enable this functionality on ArcGIS Server feature services, enable editor tracking and enable ownership-based access control on the data in the geodatabase before you publish. For hosted feature layers, enable these options from the Settings tab of the layer's item details page in the portal.
Once editor tracking is enabled on the feature layer, the editor tracking fields—the fields that store the feature creator name, feature creation date, editor name, and edit date—cannot be disabled or made invisible. If you do not include these fields in the feature layer, clients cannot take the feature layer data offline.
To use these options effectively in offline workflows, you must understand who is considered the feature creator and editor and how fields are populated.
- When you download data from the feature layer to the client for offline use, the existing values in the editor tracking fields are copied to the client along with the rest of the data.
- When editors add or alter data while offline, the date and time that features are created or edited are recorded in the appropriate date fields. These date values are preserved when the data is synchronized with the feature service.
If the date fields in the layer store values in a time zone other than UTC, you must specify that time zone when you publish the service from ArcGIS Pro. ArcGIS will apply the time zone you specify to all editor tracking date fields. If you do not specify a time zone when publishing, UTC is assumed.
If you publish a hosted feature layer from a file in ArcGIS Enterprise or ArcGIS Online, dates are always stored in UTC.
- For features created while offline, the creator name value is set to the name of the ArcGIS Enterprise or ArcGIS Online user who took the web map offline.
- When an editor updates the geometry or attributes of an existing feature while offline, the editor name value is set to the name of the ArcGIS Enterprise or ArcGIS Online user who took the web map offline. The creator name value for these features does not change.
Either the user who took the map offline or an administrator (ArcGIS Server administrator or organization administrator) can connect to the service and synchronize data.
You can control feature access using ownership-based access control. This is available for ArcGIS Server feature services and hosted feature services. Any edits the client makes that violate the ownership-based access control rules will not be synchronized with the service. The login used to synchronize the edits is considered the editor in this case.
For ArcGIS Server feature services, the ArcGIS Server administrator can also connect to the service and synchronize data. However, when an administrator synchronizes edits made while offline, ownership-based access control is based on the named user who took the map offline, not the administrator.
Editor tracking in a distributed collaboration
When using editor tracking in distributed collaboration workflows, the behaviors are as follows:
Editor tracking is enabled on feature layers for receiving organizations when it is enabled from the sending organization prior to collaboration. If you share the feature layer as a copy, the values in the editor tracking fields are reset. This reflects the fact that the data was re-created when copied into the receiving organization.
When the data is first copied to the receiving organizations, the editor tracking dates are set to the current timestamp in UTC, and creator names and editor names are set as the publishing user. When you synchronize the feature layers, the editor tracking dates from the sending organization are preserved. Therefore, from the time the data is shared onward, the receiving organization will contain the dates in which the edits were made in the sending organization. When you synchronize into the receiving organization, the creator and editor name values for features that were added or updated will be set to the feature service replica owner (publishing user) that was set when the feature layer was copied.
Access control settings are maintained for receiving organizations, but access control cannot be enforced because all features are owned by the feature service replica owner in the receiving organizations.
When a layer has editor tracking enabled in ArcGIS Online only, the sync process will set the editor tracking values based on the current time stamp (in UTC) and the feature service replica owner (publishing user).
You do not have to enable editor tracking on all layers in a feature layer. However, when you use the feature layer in a collaboration, editor tracking will get enabled on all the layers in the following scenarios:
- When sending from ArcGIS Enterprise or ArcGIS Online to ArcGIS Online, all layers will have editor tracking enabled in the hosted feature layer in ArcGIS Online.
- When collaborating from ArcGIS Online to ArcGIS Enterprise and editor tracking is enabled, all layers from feature layers in ArcGIS Online and ArcGIS Enterprise will have editor tracking enabled.
If you enable editor tracking after adding the feature layer to the collaboration, the receiving organizations will not have editor tracking enabled.