Available with Data Reviewer license.
Summary
The Find Dangles check finds polylines that have dangles within a specified tolerance.
Overview
The purpose of the Find Dangles check is to find polyline features that have nodes within a defined tolerance but are not connected to other polyline or polygon features. Dangles can occur if data has been moved or a feature has been extracted incorrectly. The polyline features are compared to other features in the same feature class or across other polyline or polygon feature classes. You can run the check on an entire feature class, a subtype, or a set of features selected using an SQL query.
Industry scenarios
The following are scenarios in which you can use this check:
- In utility networks, you can use this check to find where pipes or wires are undershoots or overshoots and do not actually connect to the rest of the network. This can affect downstream and upstream tracing results.
- In address management, it may be invalid for the street centerline feature class to have a street that is not connected to any other streets. This check can find streets that need to be connected by setting a dangle tolerance.
Supported workflows
ArcGIS Data Reviewer checks support multiple methods for implementing automated review of data. The following table identifies the supported implementation methods for this check:
| Validation | Constraint | ||
|---|---|---|---|
Reviewer batch job | Reviewer map rule | Attribute (validation) rule | No |
Yes | No | Yes (ArcGIS Pro 2.9 or later) | |
Syntax
| Parameter | Required | Description | Workflow |
|---|---|---|---|
Subtype | No | The subtype to which the rule is applied. | Validation |
Attribute | No | A query that identifies the features to which the rule is applied. | Validation |
Dangle Tolerance | Yes | The minimum distance to search for polyline nodes that are not connected to other features. Polyline features with nodes that are within this distance but not connected to other polyline features are returned as an error. The value must be greater than the input data source's x,y tolerance. The default is the data source's x,y tolerance. The default unit of measure is the input data source's horizontal spatial reference. Note:When the spatial reference of the feature class is geographic (GCS), the tolerance is converted from degrees to meters. | Validation |
Additional Features to Compare | No | Additional polyline or polygon feature classes to include in the comparison. Additional feature classes to compare must have the same datum as the input data source. | Validation |
Name | Yes | A unique name for the rule. This information is used to support data quality requirement traceability, automated reporting, and corrective workflows. | Validation |
Description | No | A description you define of the error when a noncompliant feature is found. This information is used to provide guidance to facilitate corrective workflows. | Validation |
Severity | Yes | The severity of the error assigned when a noncompliant feature is found. This value indicates the importance of the error relative to other errors. Values range from 1 to 5, with 1 being the highest priority and 5 being the lowest. | Validation |
Tags | No | The tag property of the rule. This information is used in rule authoring and management workflows to support traceability and reporting of data quality requirements. | Validation |
Notes
Keep the following in mind when using the check:
- When you configure two or more feature classes as additional features to compare, and the feature class for which you configured the check connects with one feature class but not all feature classes, this is not considered a dangle. The following images show feature 1 in orange, the additional features in gray and green, and the tolerance in blue. In image A, feature 1 does not connect to any additional features within the tolerance. This is considered a dangle with an undershoot. In image B, feature 1 connects to the gray feature, but not the green. This is an undershoot scenario when looking at it from the green feature. However, since feature 1 is connected to at least one of the features within the tolerance, this is not considered a dangle. To find connection errors with the green feature, you need to configure a check specifically for that feature.
A: Feature 1 (in orange) is returned as a dangle. 
B: Feature 1 (in orange) is not returned as a dangle. - When you configure two or more feature classes as additional features to compare, and the feature class for which you configured the check connects with one feature class but not all feature classes, this is not considered a dangle. The next images show feature 1 in orange, the additional features in gray and green, and the tolerance in blue. In image A, the endpoint of feature 1 does not connect to any additional features within the tolerance. This is considered a dangle with an overshoot. In image B, the endpoint of feature 1 connects to the green feature, but not the gray. This is an overshoot scenario when looking at it from the gray feature. However, since feature 1 is connected to at least one of the features within the tolerance, this is not considered a dangle. To find connection errors with the feature in gray, you need to configure a check specifically for that feature.
A: Feature 1 (in orange) is returned as a dangle. 
B: Feature 1 (in orange) is not returned as a dangle. - When you configure a polygon as an additional feature to compare, if the line endpoint does not touch an edge or vertex of the polygon that is within the specified tolerance, it is considered a dangle. Image A shows that the line endpoint and the polygon are within the tolerance, which is shown in blue, but the line endpoint does not touch the polygon edge or vertex; this is considered a dangle and is returned as an error. Image B is not considered a dangle and is not returned as a error.
A: Feature 1 (in orange) is returned as a dangle. 
B: Feature 1 (in orange) is not returned as a dangle. - The Validation Status attribute value of both the input features and data sources included in the Additional Features to Compare parameter are ignored during evaluation. For example, input polyline features with a validation status of 0 (No calculation required, no validation required, no error), 1 (No calculation required, no validation required, has error(s)), 4 (Calculation required, no validation required, no error), or 5 (Calculation required, no validation required, has error(s)) are still included during rule evaluation.
- Data sources for the Additional Features to Compare parameter must include a global ID field.
- Include the data sources for the Additional Features to Compare parameter when sharing web layers with the Validation capability enabled.
- The Attribute filter parameter is limited to comparison (=, <>, >, <, >=, <=) and logical (AND/OR, IN/NOT IN, LIKE/NOT LIKE, IS NULL) operators.