To work with a map even when you're offline, you can enable a sync capability on the feature services you use in your map. The sync capability has operations that allow 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.
ArcGIS clients and developer SDKs will progressively add support for the sync capability in feature services, which was introduced in ArcGIS 10.2.1. The first clients to support working with maps while offline are Collector for ArcGIS and ArcGIS Runtime SDKs. You cannot enable the sync capability on feature services published prior to ArcGIS 10.2.1.
Other clients can access the sync capability through the ArcGIS REST API.
To use the sync capability, all the data in the feature service must be from an enterprise geodatabase. Also, you must prepare the data so it can be used offline and, if required, synchronized through the feature service when you have connectivity.
The data you use in a sync-enabled feature service can be either nonversioned with archiving enabled or, if your organization's data or workflows require it, the data can be versioned.
Be aware that you can only enable the sync capability when all the data in the map is configured exactly the same; you cannot have a mix of versioned and nonversioned data.
Nonversioned data with archiving
You can use archive-enabled, nonversioned data in a feature service that is enabled for sync functionality. When the data is nonversioned, clients always work with the current representation of the data. Back-office processes are not required for clients running offline to obtain the latest changes once they again have connectivity to the feature service.
Prepare nonversioned data as follows to participate in sync functionality:
- Enable archiving on the datasets.
- Include Global IDs on the datasets.
- Relationship classes and attachments must use a Global ID primary key. For more information, see the Attachments and relationship classes section of this topic.
For a detailed walk-through of this scenario, see Tutorial: Configure feature service data for offline use.
You can publish feature services that reference nonversioned data from a 10.2 or later release enterprise geodatabase, take the data offline for editing, and synchronize changes with the enterprise geodatabase through the feature service.
If your organization requires any of the following, use versioned data:
- The data participates in geodatabase functionality that requires it to be versioned to allow editing. For example, if the feature class participates in a geometric network, the feature dataset must be registered as a traditonal version.
- Your organization has workflows in place that require the data to use traditional versioning, such as having a quality assurance version of the data.
Only traditional versioning is supported. You cannot use branch versioning with synchronization workflows at this time.
Prepare data as follows if you need to use versioning:
- Include Global IDs on the datasets.
- Register the datasets as versioned.
- Relationship classes and attachments must use a Global ID primary key. For more information, see the Attachments and relationship classes section of this topic.
You can publish feature services that reference versioned data from a 10.1 or later release enterprise geodatabase, take the data offline for editing, and synchronize changes with the enterprise geodatabase through the feature service.
See Offline maps and versioned data for more information.
The Global IDs you add to the datasets you take offline cannot be based on a custom field; they must explicitly use the Global ID field created by ArcGIS. To add Global IDs to your data, use the Add Global IDs geoprocessing tool or the Add Global ID command found on the feature class, feature dataset, and table context menus in the Catalog tree.
Attachments and relationship classes
If the data you want to use offline contains attachments or participates in a relationship class, the relationship between the tables or the table and the attachment must use either a Global ID column or user-managed field as the primary key. If the ObjectID column is the primary key, an error is returned when you download data for offline use. You can use the Migrate Relationship Class geoprocessing tool to convert ObjectID-based relationship classes and attachments to use Global ID fields as the primary key.
The GIS Server site's managed database
If you enable the sync capability at the time that you publish to the GIS Server site and you choose to copy the data to the site's managed database, no data preparation is required. The publishing process will set up the data to support the sync capability automatically. If data is not copied to the site's managed database when you publish or you enable the sync capability after publishing and copying data to the managed database, you must prepare your geodatabase data as described in the previous sections.
You can use editor tracking with data that is edited while offline. When you download data 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 working with the data offline, the date and time that features are created or edited are recorded in the create and edit date fields, respectively. These values are preserved when the data is synchronized with the service.
If your date fields store values in a time zone other than UTC, specify that time zone when you publish the service. If you do not, UTC is assumed. ArcGIS will apply the time zone you specify to all editor tracking date fields.
Offline data includes the name of the user who took the map offline. This is used with editor tracking as follows:
- For features that were created while offline, the creator name value is set to the user who took the map offline.
- For existing features that were edited while offline, the editor name value is set to the user who took the map offline. The creator name value for these features is not changed.
Either the person who took the map offline or an ArcGIS Server administrator can connect to the service and synchronize data.
Editor tracking in 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. When the data is first copied to the receiving organizations, the editor tracking values are reset where dates are set to the current timestamp in UTC and creators and editors are set as the publishing user. The reset values reflect newly copied data into a new organization. When syncing, the editor tracking dates from the sending organization are preserved. Therefore, from the time the data is shared on forward, the receiving organization will contain the dates in which the edits were made in the sending organization. Creator and editor values for inserts and updates synced into the receiving organization will be set to the replica owner (publishing user) from when the feature layer was copied.
It is possible for editor tracking to be enabled on some layers but not others within feature layers in a collaboration. In this case, when sending from ArcGIS Enterprise or ArcGIS Online, all layers will have editor tracking enabled in the hosted feature layer in ArcGIS Online. Where layers in ArcGIS Online and ArcGIS Enterprise have editor tracking enabled, the behavior is as described above. 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 and the replica owner (publishing user.)
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.
Access control settings are maintained for receiving organizations but have no consequence since all features are owned by the replica owner in the receiving organizations.
Feature layers you publish from ArcGIS Pro that reference your registered data can include attribute rules. When you edit the feature layer, ArcGIS applies the attribute calculation and constraint rules you defined in the geodatabase. Any time an edit violates one of these rules, the editor receives an error. However, if you edit the data while offline, the attribute rule information is not included in the offline data. When you synchronize the data with the feature layer, the rules are applied at that time. How the violations are treated depends on how the data is registered.
- If you use data that is registered as versioned, attribute rule violations prevent the synchronization process from taking place. Synchronization returns an error when an edit violates an attribute rule. You must correct the violation in the offline version of the data and try to synchronize again.
- If you use archive-enabled, nonversioned data, synchronization completes but edits that violate attribute rules are not applied. Information is written to the ArcGIS Server log for the edits that did not synchronize. If you use nonversioned data and attribute rules, you should always check the ArcGIS Server log after synchronizing to see which (if any) edits were not synchronized. Correct the violation in the offline version of the data and synchronize again.
Hosted feature services
If you are publishing feature services hosted on ArcGIS Online (hosted feature layers), the data is always nonversioned and is automatically prepared to use sync when you enable sync capabilities. This is done because publishers do not have access to the ArcGIS Online hosting server and, therefore, could not manually prepare the data to use sync capabilities.
When you publish hosted feature layers to Portal for ArcGIS, the data is copied to the managed database of the portal's hosting server. This data is also always nonversioned. If your portal's hosting server uses an ArcGIS Data Store relational data store for the managed database, the data is automatically prepared to use sync when you enable sync capabilities. If you are not using a relational data store for the managed database, you may need to alter the data manually to synchronize. For more information, see Enable a hosted feature service for offline mapping in the Portal for ArcGIS help.
ArcGIS Enterprise 10.5.1 was the last release that allows the use of an enterprise geodatabase as the managed database for a hosting server. If you are configuring a new hosting server, use a relational ArcGIS Data Store.
Feature service preparation
When authoring a feature service, the publisher chooses options that define the edits that can be made through the service. The following sections describe how the options are applied when using maps offline.
Operations allowed (capabilities)
Feature service capabilities define the operations that are allowed when working with a feature service. 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.
- Editable data—If clients will edit the data when offline and synchronize changes with the feature service when they have connectivity, set the following capabilities on the feature service:
- Any combination of Create, Delete, and Update
Once the feature service is created, publishers and administrators can choose to disable the sync capability. For example, a publisher or administrator might 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.
Allowed operations apply only to nonadministrative users such as members of an ArcGIS Server publisher or user role. 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.
If you are using nonversioned data, avoid keeping edit transactions open for long periods of time when editing a sync-enabled feature service. For example, if you plan to edit nonversioned data in ArcMap that is also used for sync by a feature service, make sure to save edits periodically and stop editing when the edit session is complete.
Geometry updates and true curves
The feature service can be configured 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.
Ownership-based access control
You can control feature access using ownership-based access control. Any edits the client made 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.
Either the person who took the map offline or an ArcGIS Server administrator can connect to the service and synchronize data. 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.
Invisible and read-only fields
When you author a feature service, you can choose to make some fields read-only or not visible to the feature service. Fields that are not visible to the feature service will not be downloaded to the client for offline use. Read-only fields will remain read-only in the downloaded data.
The following must be visible when you enable the sync capability; otherwise, your map cannot be taken offline.
- The primary and foreign key fields if a relationship class is present
- Editor tracking fields if editor tracking is enabled
A feature service published to ArcGIS Server or Portal for ArcGIS that contains two layers based on the same feature class cannot be taken offline, edited, and synchronized.
For example, if you add your roads feature class to your map to display all roads, add the same roads feature class and set a definition query on it to display roads that are under construction, and publish a feature service from the map, you cannot take the feature service offline for editing and synchronize your changes when you are online.
When an editable feature service contains versioned data, a version is created for individual clients when a map is taken offline. When a client synchronizes changes to the feature service, edits are applied to this version. The geodatabase administrator must perform reconcile and post processes to share the edits with others.
When a read-only feature service (only Query and Sync capabilities enabled) contains versioned data, no version is created. When a client synchronises with the published version, changes to the published feature service are automatically available in the client.
By default, a version is created every time someone takes a map offline that contains an editable feature service. However, the ArcGIS Server administrator or feature service owner can configure the feature service so a version is created for each login.
For example, if five different field workers take a map offline, five versions are generated. Each version is specific to an individual login, and the version name is based on the login name and the service name (for example, Joe_ValveFS). If Joe takes the map offline multiple times (for example, from more than one device), the same version is used when Joe syncs from each device. Thus one device has access to edits from the other device. However, new offline maps will only be as up-to-date as the last time Joe's version was reconciled. A version will remain as long as the person who took the map offline still has the offline map.
The names of versions created for synchronization are limited to 30 bytes.
Follow these steps to set this sync option on an ArcGIS Server service:
- Log in to ArcGIS Server Manager as the service owner or ArcGIS Server administrator.
- Be sure Services is selected at the top of ArcGIS Server Manager.
- Browse to your feature service and click the service's name to open information on that service.
- Click Capabilities.
- Select Feature Access.
- Under Properties, click Advanced Options.
The Feature Service Advanced Options dialog box opens.
- Under Sync, choose to Create a version for each Downloaded Map or User.
- Click OK to close the Feature Service Advanced Options dialog box.
- Click Save and Restart to apply the setting changes to your feature service.
The service will be unavailable while it is restarting.
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.
System information for synchronization processes
When data is downloaded for offline map use or changes are synchronized back to the service, information about these processes is stored in the system tables of the enterprise geodatabase that the feature service is using for its source data. The feature service's replicas resource lists metadata for the feature service. If the service is secured, only metadata associated with the logged in user or anonymous user is listed. Geodata services also include a replicas resource, which lists metadata for all feature services that reference the geodatabase. Administrators can use geodata services for tasks such as listing metadata per service or removing metadata for feature services that have been removed.