Skip To Content

Dissolve Boundaries

Summary

Finds polygons that intersect or have the same field values and merges them to form a single polygon.

Which boundaries are merged can be controlled by specifying one or more fields. For example, if you have a layer of counties and each county has a State_Name field, you can dissolve boundaries using the State_Name field. Adjacent counties will be merged if they have the same value for State_Name. The result is a layer of state boundaries.

Illustration

Dissolve Boundaries workflow diagram

Usage

  • The Input Layer features must have polygon geometry. The dissolved output features will always be polygons.

  • There are two methods for dissolving boundaries: polygons that intersect and polygons that have the same field value.

    Polygon features that have intersecting boundaries will be dissolved by default. Optionally, you can use the Dissolve Field(s) parameter to dissolve intersecting polygons that have one or more of the same field values.

    For example, if you have a layer of study areas with a Soil_Type field, you can dissolve boundaries based on the attributes of the Soil_Typefield. Study areas will be merged if they have the same value for Soil_Type. The result is a layer of study areas by soil type. If two or more fields are specified, the input features must have the same value for each for the boundary to be dissolved.

  • The attributes of the features that become aggregated by dissolve can be summarized or described using a variety of statistics with the Summary Fields parameter. The statistic used to summarize attributes is added to the output feature class as a single field with the naming standard of statistic type + underscore + input field name. For example, if the SUM statistic is used on a field named POP, the output will have a field named SUM_POP.

  • Output from the Dissolve Boundaries tool can include multipart or single part features. A multipart feature is defined as one feature that is broken up into noncontiguous parts. For example, the state of Hawaii could be considered a multipart feature because its separate geometric parts are classified as a single state. The Create multipart features parameter offers two options when deciding to create multipart or single part output:

    • True (checked)—The output will create any multipart features if applicable.
    • False (unchecked)—Only single part features will be created in the output. This is the default.

  • The following table outlines how the Create multipart features parameter operates with the dissolve options:

    Dissolve methodMultipart is false (default)Multipart is true

    If you do not specify Dissolve Field(s) (default), make sure the text matches the UI

    All features dissolved with multipart false

    Three features are created when all values are dissolved and multipart is false. Only overlapping features are dissolved.

    All features dissolved with multipart true

    One feature is created when all values are dissolved and multipart is true. When you select this option, the result will always be one feature.

    If you specify Dissolve Field(s)

    Features with like values dissolved with multipart false

    Four features are created when the dissolve is applied based on the field (here, the field is the color of input points). Only overlapping features with the same value of the specified fields are dissolved.

    Features with like values dissolved with multipart true

    Two features are created when the dissolve is applied based on the field (here, the field is the color of input points) and multiparts are allowed. Values with the same field value will always be a single feature.

  • This geoprocessing tool is powered by ArcGIS GeoAnalytics Server. Analysis is completed on your GeoAnalytics Server, and results are stored in your content in ArcGIS Enterprise.

  • When running GeoAnalytics Tools, the analysis is completed on the GeoAnalytics Tools. For optimal performance, data should be available to the GeoAnalytics Tools through feature layers hosted on your ArcGIS Enterprise portal or through big data file shares. Data that is not local to your GeoAnalytics Tools will be moved to your GeoAnalytics Tools before analysis begins. This means that it will take longer to run a tool, and in some cases, moving the data from ArcGIS Pro to your GeoAnalytics Tools may fail. The threshold for failure depends on your network speeds, as well as the size and complexity of the data. Therefore, it is recommended that you always share your data or create a big data file share.

Syntax

DissolveBoundaries_geoanalytics (input_layer, output_name, {multipart}, {dissolve_fields}, fields, {summary_fields}, {data_store})
ParameterExplanationData Type
input_layer

The layer containing the polygon features that will be dissolved.

Feature Set
output_name

The name of the output feature service.

String
multipart
(Optional)

Specifies whether multipart features can be created in the output feature class.

  • MULTI_PARTMultipart features are allowed.
  • SINGLE_PARTMultipart features are not allowed. Instead of creating multipart features, individual features will be created for each part. This is the default.
Boolean
dissolve_fields
(Optional)

Specifies whether features with the same field values will be dissolved.

  • NO_DISSOLVE_FIELDSPolygons that share a common border (that is, they are adjacent) or polygons that overlap will be dissolved into one polygon. This is the default.
  • DISSOLVE_FIELDSPolygons that have the same field value or values will be dissolved.
Boolean
fields
[fields,...]

The field or fields to use to dissolve like features. Features with the same value for each field will be dissolved.

Field
summary_fields
(Optional)

The statistics that will be calculated on specified fields.

  • COUNT—Calculates the number of nonnull values. It can be used on numeric fields or strings. The count of [null, 0, 2] is 2.
  • SUM—The sum of numeric values in a field. The sum of [null, null, 3] is 3.
  • MEAN—The mean of numeric values. The mean of [0,2, null] is 1.
  • MIN—The minimum value of a numeric field. The minimum of [0, 2, null] is 0.
  • MAX—The maximum value of a numeric field. The maximum value of [0, 2, null] is 2.
  • STDDEV—The standard deviation of a numeric field. The standard deviation of [1] is null. The standard deviation of [null, 1,1,1] is 1.
  • VAR—The variance of a numeric field in a track. The variance of [1] is null. The variance of [null, 1,1,1] is 1.
  • RANGE—The range of a numeric field. This is calculated as the minimum value subtracted from the maximum value. The range of [0, null, 1] is 1. The range of [null, 4] is 0.
  • ANY—This is a sample string from a field of type string.

Value Table
data_store
(Optional)

Specifies the ArcGIS Data Store where the output will be saved. The default is SPATIOTEMPORAL_DATA_STORE. All results stored to the SPATIOTEMPORAL_DATA_STORE will be stored in WGS84. Results stored in a RELATIONAL_DATA_STORE will maintain their coordinate system.

  • SPATIOTEMPORAL_DATA_STOREOutput will be stored in a spatiotemporal big data store. This is the default.
  • RELATIONAL_DATA_STOREOutput will be stored in a relational data store.
String

Derived Output

NameExplanationData Type
output

The dissolved output.

Record Set

Code sample

DissolveBoundaries example (stand-alone script)

The following stand-alone script demonstrates how to use the DissolveBoundaries tool.

# Name: Dissolve_County_Boundaries.py
# Description: Dissolve county features based on common state name attributes
# Requirements: ArcGIS GeoAnalytics Server
 
# Import system modules
import arcpy
 
# Set local variables
inputLayer = "https://sampleserver6.arcgisonline.com/arcgis/rest/services/USA_counties/FeatureServer/0"
outputName = "USA_State_Boundaries"
statistics = [["population", "SUM"]]
dataStore = "RELATIONAL_DATA_STORE"
  
# Execute DissolveBoundaries using "STATE" as the Dissolve Field
arcpy.geoanalytics.DissolveBoundaries(inputLayer, outputName, "SINGLE_PART",
                                      "DISSOLVE_FIELDS", "STATE", statistics, dataStore)

Environments

Output Coordinate System

The coordinate system that will be used for analysis. Analysis will be completed on the input coordinate system unless specified by this parameter. For GeoAnalytics Tools, final results will be stored in the spatiotemporal data store in WGS84.

Licensing information

  • Basic: Requires ArcGIS GeoAnalytics Server
  • Standard: Requires ArcGIS GeoAnalytics Server
  • Advanced: Requires ArcGIS GeoAnalytics Server

Related topics