The Dissolve tool finds polygons or polylines that overlap or share a common boundary or share common attributes, and merges them to form a single polygon or polyline.
Examples
The Dissolve tool can be used in scenarios such as the following:
- Combine multiple study area polygons into a single polygon that represents the boundary of the study.
- Create a single polyline out of intersecting trail segments.
- Aggregate (dissolve) geometries based on matching attribute values.
Parameters
The following table outlines the parameters used in the Dissolve tool:
| Parameter | Description |
|---|---|
Input dataset | The dataset containing the geometry field to dissolve. |
Geometry field | The polygon or polyline field that will be dissolved. |
Dissolve records with matching field values | Dissolve geometries based on matching field values. |
Fields to match | Specifies one or more fields that will be used to dissolve geometries based on matching values. |
Create multipart geometries | Specifies whether the output can contain multipart geometries. |
Summary fields | The fields from the input dataset that will be summarized, and the statistics that will be calculated for each field. |
Usage notes
Use the Input dataset parameter to identify the dataset that contains the geometries to dissolve.
The Dissolve records with matching field values parameter determines whether the tool dissolves only the geometries that intersect and have the same field value (enabled), or only the geometries that intersect (disabled).
The Create multipart geometries parameter determines whether the output can contain multipart geometries. A multipart geometry is defined as one geometry that is broken up into noncontiguous parts. For example, the state of Hawaii could be considered a multipart geometry because its separate geometric parts are classified as a single state. The Create multipart geometries parameter includes two options:
- True (enabled)—Multipart geometries will be created in the output if applicable.
- False (disabled)—Only single-part geometries will be created in the output. This is the default.
The Summary fields parameter determines which fields from the input dataset to summarize. The statistics are calculated using the records that are dissolved together. The following summary statistics are available:
- Sum—The sum of numeric values in a field. The sum of [null, 1, 3] is 4.
- Min—The minimum value of a numeric or date field. The minimum of [0, 2, null] is 0.
- Max—The maximum value of a numeric or date field. The maximum of [0, 2, null] is 2.
- Mean—The mean of numeric values. The mean of [0, 2, null] is 1.
- Standard deviation—The standard deviation of a numeric field. The standard deviation of [null, 1, 1, 1] is 0.
- Count—The number of nonnull values. It can be used on a field of any type. The count of [null, "hello", "world"] is 2.
- Any—A sample value from a field of any type.
The following table outlines how the Create multipart geometries parameter operates with different dissolve options:
| Dissolve method | Input dataset | Multipart is false (default) | Multipart is true |
|---|---|---|---|
Fields to match is not specified (default). |  The input dataset contains six geometries. Some of the geometries intersect with others, and one is isolated from others. |  Three geometries are created when all values are dissolved and multipart is false. Only overlapping geometries are dissolved. |  One geometry is created when all values are dissolved and multipart is true. With this parameter combination, the result will always be one geometry. |
Fields to match is specified. |  The input dataset contains six geometries. Some of the geometries intersect with others, and one is isolated from others. Three share the attribute blue and three share the attribute yellow. |  Four geometries are created when the dissolve is applied based on the field (here, the field is the color of input polygons). Only overlapping geometries with the same value of the specified fields are dissolved. |  Two geometries are created when the dissolve is applied based on the field (here, the field is the color of input polygons) and multiparts are allowed. Values with the same field value will always be a single geometry. |
Outputs
In addition to any fields specified using the optional Fields to match parameter, the following fields will be available in the output result:
| Field name | Description |
|---|---|
COUNT | The count of records that have been dissolved into the new geometry. This is always included in the output. |
STATISTIC_fieldname | Specified statistics will each create an attribute field, named in the following format: STATISTIC_fieldname. For example, the mean of the measurement field is MEAN_measurement. |
GEOMETRY | The polygon or polyline geometry field containing the dissolved result. |
Limitations
The following are known limitations for the Dissolve tool:
- The input geometry must be of type polyline or polygon. Points and multipoints are not supported.
- Records with empty, null, or invalid geometries will be excluded from processing and their values will not be used in summary statistic calculations.
Licensing requirements
The following licensing and configurations are required:
- Creator or Professional user type
- Publisher, Facilitator, or Administrator role, or an equivalent custom role
To learn more about Data Pipelines requirements, see Requirements.