Work with feeds

A feed is a real-time stream of data coming into ArcGIS Velocity. Feeds typically connect to external sources of observational data such as Internet of Things (IoT) platforms, message brokers, or third-party APIs. Feeds parse incoming tabular, point, polyline, or polygon data and expose it for analysis and visualization. A feed is also a type of stream layer and can be added to a map, allowing you to visualize information as soon as it is received.

The following feed types are available in ArcGIS Velocity:

Examples

The following are examples of using a feed:

  • A transportation agency asset manager creates an Azure Event Hub feed to receive observational data from IoT sensors situated along a roadway.
  • A GIS analyst creates a Feature Layer feed to ingest new features from a feature layer being edited by hundreds of users in a web app.

Polling and streaming feeds

There are two primary types of feeds in ArcGIS Velocity: polling feeds and streaming feeds.

A polling feed polls the specified source of data at a user-defined interval such as every 10 seconds or every minute. Examples of polling feeds include Feature Layer, HTTP Poller, and RSS. When a polling interval is set, the polling occurs at regular time intervals as opposed to the start time of the feed. For example, if a feed is set to poll for data every 5 minutes, and the feed is started at 8:03 a.m., the first request for data will occur at 8:05 a.m., the next at 8:10 a.m., and so on.

A streaming feed connects to the specified source of streaming data and remains connected. Any time the source sends additional data, the streaming feed immediately receives and processes the data into events. Examples of streaming feeds include Stream Layer, MQTT, and Kafka.

Start and stop a feed

A feed can be in either a started (running) or stopped state. A feed only receives or polls its data source when it is in a started state. When you create a feed, it starts automatically.

You can stop a feed to stop ingesting event data. When you edit a started feed, it restarts once the edits are saved.

Create a feed

To create a feed, follow the steps below:

  1. Open the ArcGIS Velocity app.
  2. Click Create feed.
  3. Choose the feed type to create by browsing the groups of feeds or by searching using a keyword. Feed types are grouped into the following categories:
    • ArcGIS
    • Cloud
    • Web and Messaging
    • Data Providers
  4. Select the feed type.
  5. Provide the feed configuration details. The configuration parameters vary depending on the feed type.
  6. Click Next to continue with the remaining steps including confirming the schema, identifying the key fields, defining the polling interval (if applicable), and saving the feed.

For more information, see Configure input data and the Create a feed quick lesson.

Edit a feed

You can edit an existing feed, allowing you to update connection parameters, schema configuration, key fields, and polling settings. If the feed was running before you started editing, it restarts automatically after you save your edits and the changes take effect immediately.

You can edit a feed in two places in the ArcGIS Velocity app:

  • On the Feeds list page, click the edit button associated with the feed you want to edit.
  • On the Feeds details page, click Edit to edit the parameters.

Edit a feed's symbology

You can edit an existing feed's symbology, allowing you to define how raw feature are rendered. Individual features are only rendered when the number of features to be rendered in the current map extent is less than the feature threshold specified. Raw feature rendering of the feed is limited to simple vector symbols (circles, squares, diamonds, pointers, and more).

To edit a feed's symbology, follow the steps below:

  1. Open the ArcGIS Velocity app.
  2. Click Feeds from the menu on the left.
  3. Identify the an existing feed in the Feeds list page.
  4. On the existing feed, click Edit symbology to open the Feature settings pane.
  5. For Renderer, choose Simple, Class Breaks, or Unique Value and set the parameters. More information about the rendering options and parameters is below.

Simple

Raw features can be rendered using the Simple renderer option. The simple renderer renders all features in a stream layer with the same symbol. The simple renderer allows you to choose either Basic shapes or Arrows using the Symbol category parameter.

Simple renderer

The Simple renderer parameters are described in the following table:

ParameterDescription

Symbol (fill)

The symbol style used to render features. Options are circle, square, diamond, triangle, cross, X, and pointer.

Size (fill)

The size of the feature.

Color (fill)

The color of the feature.

Color (outline)

The color of the outline.

Width (outline)

The width of the outline.

Feature rotation

Specifies whether features should be rotated.

Rotation type

The rotation type used to rotate the simple marker symbols. The rotation type controls the origin and direction of rotation. If the rotation type is Arithmetic, the symbol is rotated from east in a counter-clockwise direction, where east is the 0° axis. If the rotation type is Geographic, the symbol is rotated from north in a clockwise direction, where north is the 0° axis.

  • Arithmetic—0° is east and advances counter-clockwise.
  • Geographic—0° is north and advances clockwise.

Rotation field

The field containing the values to use for rotation.

Rotation angle

The angle of all features relative to the screen in degrees.

Class breaks

Raw features can be rendered using the Class Breaks renderer option. The class breaks renderer defines the symbol for each feature in a feature layer based on the value of a numeric attribute. The numeric attribute values are used to define data ranges for the classes. Each feature is assigned a symbol based on the class break of its numeric attribute value.

Class breaks renderer

The Class Breaks renderer parameters are described in the following table:

ParameterDescription

Classify data

Specifies the classification method. Options are manual breaks, natural breaks, equal interval, standard deviation, and quantile.

Class breaks field

Specifies the field used for calculating class break values.

Class count

The total number of classes. The classes can be manually adjusted in the class breaks histogram.

Color ramp

Applies a range of colors to the classes. Choose one of the color ramps or apply a unique color ramp using the fill style.

Class count

The total number of classes. The classes can be manually adjusted in the class breaks histogram.

Class settings

The fill and outline settings for a respective class. Access the class settings by selecting a class break value.

Symbol (fill)

The symbol style used to render features. Options are circle, square, diamond, triangle, cross, X, and pointer.

Size (fill)

The size of the features.

Color (outline)

The color of the feature outlines.

Width (outline)

The width of the feature outlines.

Feature rotation

Specifies whether features should be rotated.

Rotation type

The rotation type used to rotate the simple marker symbols. The rotation type controls the origin and direction of rotation. If the rotation type is Arithmetic, the symbol is rotated from east in a counter-clockwise direction, where east is the 0° axis. If the rotation type is Geographic, the symbol is rotated from north in a clockwise direction, where north is the 0° axis.

  • Arithmetic—0° is east and advances counter-clockwise.
  • Geographic—0° is north and advances clockwise.

Rotation field

The field containing the values to use for rotation.

Rotation angle

The angle of the features relative to the screen in degrees.

Unique value

Raw features can be rendered using the Unique Value renderer option. The unique value renderer renders all features in a stream layer based on one or more matching attributes.

Unique value renderer

The Unique Value renderer parameters are described in the following table:

ParameterDescription

Unique value field

Specifies the field used for determining unique values.

Manage Values

Defines the unique value to symbolize. Values not present in the current data set can be manually added.

Color ramp

Applies a range of colors to the unique values.

Unique value settings

Defines the fill and outline settings for a single unique value. Access the unique value settings by selecting a unique value category.

Symbol (fill)

The symbol style used to render all features. Options are circle, square, diamond, triangle, cross, X, and pointer.

Size (fill)

The size of the features.

Color (outline)

The color of the feature outlines.

Width (outline)

The width of the feature outlines.

Feature rotation

Specifies whether features should be rotated.

Rotation type

The rotation type used to rotate the simple marker symbols. The rotation type controls the origin and direction of rotation. If the rotation type is Arithmetic, the symbol is rotated from east in a counter-clockwise direction, where east is the 0° axis. If the rotation type is Geographic, the symbol is rotated from north in a clockwise direction, where north is the 0° axis.

  • Arithmetic—0° is east and advances counter-clockwise.
  • Geographic—0° is north and advances clockwise.

Rotation field

The field containing the values to use for rotation.

Rotation angle

The angle of the features relative to the screen in degrees.

Save the feed

You can save the settings and changes you made. When you click the Save layer button, client applications such as ArcGIS Online web maps that consume the feed will be symbolized and rendered according to the settings.