Feature Layer (existing)

The Feature Layer (existing) output allows you to write output features to an existing ArcGIS feature layer. When using this output type, features will be written an existing ArcGIS feature layer, as opposed to creating a new feature layer. The existing feature layer should be of the same geometry type and contain all of the same attributes as the incoming data.


  • After ingesting real-time features from IoT sensors through a feed and a real-time analytic, an asset manager wants to add those observations to an existing feature layer.
  • A GIS analyst performs analysis of the latest information in a big data analytic and appends the results to an existing layer that is already in use in various applications.
  • A business analyst ingests a set of existing, historical observations, from an external cloud store and configures a real-time analytic to process events as they occur and captures the new observations in an existing feature layer.

Usage notes

  • The selected feature layer must be hosted by Velocity.
  • The schema of the incoming data and the destination feature layer must generally match. Each should have the same geometry type, spatial reference, and the fields present in the incoming data should exist in the destination feature layer. Differences can include:
    • The destination feature layer can have additional fields not present in the incoming data that may be used for data enrichment.
    • The Map Fields tool can be used to transform the schema of the incoming data in an analytic workflow to align with the schema of the output feature layer.
  • A data retention policy is required for all output feature layers since data will grow over time. When writing to an existing feature layer and choosing the Data Storage Method of Add New Features, the selected feature layer must have a data retention policy other than No Purge. For more information, see About data retention.
  • When Editor tracking is enabled and the Data Storage Method is set to Add new features, the creator and editor user and date will always be the same. If the Data Storage Method is set to Keep latest feature, a track observation that is updated will only have the editor user and date updated after the first observation.


ParameterDescriptionData Type

Feature Service Portal Item ID

The Portal Item ID of the corresponding feature layer item created in ArcGIS Online.

The feature layer must belong to the user creating the analytic.


Data Storage Method

Controls whether all new features are added to the layer or if existing features are updated. Options include:

  • Add New Features - All new features will be added to the feature layer.
  • Keep Latest Feature - Only the latest feature for each unique Track ID will be kept. The output data schema should have a Track ID and Start Time key fields identified.


Creator or editor username

Specifies the username to use as the creator or editor for processed data. The username can be derived from a field of the incoming data or set as the username of the analytic owner.

The Creator or editor username parameter only applies and is shown when the existing feature layer already has editor tracking enabled.

For details, see Usage notes.


Considerations and limitations

  • The selected feature layer must be hosted by Velocity.