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Dissolve Boundaries

Dissolve BoundariesThe Dissolve Boundaries tool merges area features that either intersect or have the same field values.

Workflow diagram

Dissolve Boundaries workflow diagram

Analysis using GeoAnalytics Tools

Analysis using GeoAnalytics Tools is run using distributed processing across multiple ArcGIS GeoAnalytics Server machines and cores. GeoAnalytics Tools and standard feature analysis tools in ArcGIS Enterprise have different parameters and capabilities. To learn more about these differences, see Feature analysis tool differences.

Examples

An agricultural development company sampled thousands of terrestrial quadrats across a county. The data includes a soil_depth field, and a suitability field. The suitability field was calculated by classifying soil_depth values into categories of low or high. The quadrats can be dissolved based on the suitability field to determine where the most expansive suitable area is located.

Usage notes

Specify the area feature layer you want to dissolve boundaries for using the Choose area layer whose boundaries will be dissolved parameter.

Use the Choose dissolve method parameter to define how boundaries are dissolved by selecting from one of two options:

OptionDescription

Areas that overlap or are adjacent

Two or more areas whose boundaries overlap or who share a common boundary will be merged into one area. This is the default.

Areas with the same field value

Areas will be merged into one area if they have the same field value. More than one field can be selected to merge areas.

The Allow multipart features option determines whether the results will 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 following options are available when deciding to create multipart or single part output:

OptionDescription

False (unchecked)

Only single part features will be created in the output. This is the default.

True (checked)

The output will create any multipart features if applicable.

The following table outlines how the multipart parameter operates for each dissolve option:

Dissolve methodMultipart is false (default)Multipart is true

Areas that overlap or are adjacent (default)

All features dissolved with multipart false

Three features are created when all values are dissolved and multipart is false. Only overlapping features are dissolved. This is the same as the standard analysis tool's Dissolve option. This is the default.

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.

Areas with the same field value
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.

If Use current map extent is checked, only the features that are visible within the current map extent will be analyzed. If it's not checked, all input features in the input layer will be analyzed, even if they are outside the current map extent.

Limitations

Inputs to the Dissolve Boundaries tool must be area features.

How Dissolve Boundaries Works

Calculations

Optionally, you can calculate one or more statistics for the dissolved areas by using the Add statistics parameter. The following soil depth example outlines how statistics are calculated for dissolved features with a suitability value of high.

Example features to be dissolved with calculated statistics

Example features to be dissolved. Areas can be dissolved together based on the suitability field to determine where soil is most suitable for agriculture.

Numeric statisticCalculated result

Count

Count of:

[130, 8, 250] = 3

Sum

130 + 8 + 250 = 388

Minimum

Minimum of:

[130, 8, 250] = 8

Maximum

Maximum of:

[130, 8, 250] = 250

Average

388/3 = 129.333

Variance

= 14641.33

Standard Deviation

= 121.0014

String StatisticCalculated Results

Count

["high", "high", "high"] = 3

Any

= "high"

Note:

The count statistic (for strings and numeric fields) counts the number of nonempty values. The count of [0, 1, 10, 5, null, 6] = 5. The count of [Primary, Primary, Secondary, null] = 3.

ArcGIS API for Python example

The Dissolve Boundaries tool is available through ArcGIS API for Python.

This example dissolves boundaries of soil areas in Nebraska if they have the same solubility. For dissolved features, it calculates the sum of the quadrat area, the mean soil depth, and an example of the quadrat description.

# Import the required ArcGIS API for Python modules
import arcgis
from arcgis.gis import GIS
from arcgis.geoanalytics import manage_data

# Connect to your ArcGIS Enterprise portal and confirm that GeoAnalytics is supported
portal = GIS("https://myportal.domain.com/portal", "gis_publisher", "my_password", verify_cert=False)
if not portal.geoanalytics.is_supported():
    print("Quitting, GeoAnalytics is not supported")
    exit(1)   

# Find the Feature Layer containing the features you want to dissolve and apply a filter
dissolve_features_search = portal.content.search("study_areas", "Feature Layer")
dissolve_features = dissolve_features_search[0].layers[0]
dissolve_features.filter = "region = 'Nebraska'"

# Define the fields containing the values used to dissolve features
dissolve_fields = "soil_suitability"

# Define the statistics to calculate for dissolved areas 
summary_fields = [{"statisticType" : "Sum", "onStatisticField" : "quadrat_area_km2"},
                  {"statisticType" : "Mean", "onStatisticField" : "soil_depth_cm"},
                  {"statisticType" : "Any", "onStatisticField" : "quadrat_desc"}]


# Set the tool environment settings
arcgis.env.out_spatial_reference = 3310
arcgis.env.output_datastore= "relational"
arcgis.env.defaultAggregations= True

# Run the Dissolve Boundaries tool
dissolve_result = manage_data.dissolve_boundaries(input_layer = dissolve_features,
                                                  dissolve_fields = dissolve_fields,
                                                  summary_fields = summary_fields,
                                                  multipart = True,
                                                  output_name = "Soil_Suitability_dissolved")

# Visualize the tool results if you are running Python in a Jupyter Notebook
processed_map = portal.map('Nebraska')
processed_map.add_layer(dissolve_result)
processed_map

Similar tools

Use Dissolve Boundaries when you want to aggregate intersecting areas or areas with the same field value into a single area. Other tools may be useful in solving similar but slightly different problems.

Map Viewer analysis tools

Create buffered areas and dissolve buffers that intersect or have the same field value using the ArcGIS GeoAnalytics Server tool Create Buffers.

Combine two layers into a single layer using Intersect or Erase methods using the ArcGIS GeoAnalytics Server tool Overlay Layers.

ArcGIS Desktop analysis tools

To run this tool from ArcGIS Pro, your active portal must be Enterprise 10.7 or later. You must sign in using an account that has privileges to perform GeoAnalytics Feature Analysis.

Perform similar dissolve operations in ArcGIS Pro with the Dissolve geoprocessing tool.