Production Dissolve

Available with Production Mapping license.

Summary

Aggregates features based on specified attributes.

Learn more about how Dissolve works

Usage

• The attributes of the features that become aggregated by dissolve can be summarized by using a variety of statistics.

  Note:

  However, each Field can be used only once in the Calculate Fields pane since the tool modifies the attributes and geometry in the original feature class without modifying the database's schema.

• This tool can create very large features in the output feature class. This is especially true when there is a small number of unique values in the Dissolve Fields or when dissolving all features into a single feature. Very large features may cause processing or display problems and have poor performance when drawn on a map or when edited. Problems may also occur if the dissolve output creates a feature at the maximum size on one machine, and then this output gets moved to a machine with less available memory. To avoid these problems, use the SINGLE_PART option on the Create multipart features parameter to split potentially large multipart features into smaller features. For extremely large features created by this tool, the Dice tool may have to be used.

• Null values are excluded from all statistical calculations. For example, the AVERAGE of 10, 5, and NULL is 7.5 ((10+5)/2). The COUNT tool returns the number of values included in the statistical calculation, which in this case is 2.

• This tool will use a tiling process to handle very large datasets for better performance and scalability. For more details, see Tiled_processing_of_large_datasets.

• The availability of physical memory may limit the amount (and complexity) of input features that can be processed and dissolved into a single output feature. This limitation could cause an error to occur, as the dissolve process may require more memory than is available. To prevent this, Production Dissolve may divide and process the input features using an adaptive tiling algorithm. To determine the features that have been tiled, run the Frequency tool on the result of this tool, specifying the same fields used in the dissolve process for the Frequency Fields parameter. Any record with a frequency value of 2 has been tiled. Tile boundaries are preserved in the output features to prevent the creation of features that are too large to be used by ArcGIS.

  Caution:

  Running Production Dissolve on the output of a previous dissolve run will rarely reduce the number of features in the output when the original processing divided and processed the inputs using adaptive tiling. The maximum size of any output feature is determined by the amount of available memory at run time; therefore, output containing tiles is an indicator that dissolving any further with the available resources would cause an out-of-memory situation or result in a feature that is unusable. Additionally, running the Production Dissolve tool a second time on output that was created this way may cause very slow performance for little to no gain and may cause an unexpected failure.

• The Dissolve Fields parameter's Add Field button is used only in ModelBuilder. In ModelBuilder, where the preceding tool has not been run, or its derived data does not exist, the Dissolve Fields parameter may not be populated with field names. The Add Field button allows you to add expected fields so you can complete the tool's dialog box and continue to build your model.

• The Unsplit lines parameter with two options, DISSOLVE_LINES and UNSPLIT_LINES, only applies to line input. When the default DISSOLVE_LINES option is specified, lines are dissolved into a single feature. When UNSPLIT_LINES is specified, only two lines that have a common endpoint (known as a pseudonode) are merged into one continuous line.

• If the Input Features geometry type is either point or multipoint and Create multipart features is checked (in Python, multi_part is set to MULTI_PART), the output will be a multipoint feature class. Otherwise, if Create multipart features is unchecked (in Python, multi_part is set to SINGLE_PART), the output will be a point feature class.

Syntax

arcpy.production.ProductionDissolve(input_features, {dissolve_fields}, {calculate_fields}, {dissolve_option}, {create_multipart}, {unsplit_lines})

Parameter	Explanation	Data Type
input_features	The features to be aggregated. If the layer has a selection, the tool will run on that selection.	Feature Layer
dissolve_fields [dissolve_fields,...] (Optional)	The field or fields on which to aggregate features. The Add Field button, which is used only in ModelBuilder, allows you to add expected fields so you can complete the dialog box and continue to build your model.	String
calculate_fields [[field_name, statistic],...] (Optional)	The fields and statistics with which to summarize attributes. Text attribute fields may be summarized using the statistics FIRST or LAST. Numeric attribute fields may be summarized using any statistic. Strings and other non-numeric field types will not be calculated. Nulls are excluded from all statistical calculations. FIRST—Finds the first record in the Input Features and uses its specified field value. LAST—Finds the last record in the Input Features and uses its specified field value. SUM—Adds the total value for the specified field. MEAN—Calculates the average for the specified field. MIN—Finds the smallest value for all records of the specified field. MAX—Finds the largest value for all records of the specified field. RANGE—Finds the range of values (MAX–MIN) for the specified field. STD—Finds the standard deviation on values in the specified field. COUNT—Finds the number of values included in statistical calculations. This counts each value except null values. To determine the number of null values in a field, use the COUNT statistic on the field in question, and a COUNT statistic on a different field which does not contain nulls (for example, the OID if present), then subtract the two values.	Value Table
dissolve_option (Optional)	Indicates whether the first or the last feature will be used to populate the non-dissolve and non-calculate fields. FIRST — Utilizes the feature with the lowest ObjectID to populate the non-dissolve and non-calculate fields. LAST — Utilizes the feature with the highest ObjectID to populate the non-dissolve and non-calculate fields. USE_DEFAULTS — Populates the non-dissolve and non-calculate fields with the default value from the field or subtype when applicable.	String
create_multipart (Optional)	Specifies whether multipart features are allowed in the output feature class. MULTI_PART —Specifies multipart features are allowed. This is the default. SINGLE_PART —Specifies multipart features are not allowed. Instead of creating multipart features, individual features will be created for each part.	Boolean
unsplit_lines (Optional)	Controls how line features are dissolved. DISSOLVE_LINES —Lines are dissolved into a single feature. This is the default. UNSPLIT_LINES —Lines are only dissolved when two lines have an end vertex in common.	Boolean

Derived Output

Name	Explanation	Data Type
output_feature_layer	Includes the modified features from the original input.	Feature Layer

Code sample

The following Python window script demonstrates how to use the ProductionDissolve geoprocessing tool.

# Name: ProductionDissolve_Example.py
# Description: Dissolve features based on common attributes

# Import system modules
import arcpy

# Check out extension
arcpy.CheckOutExtension("Foundation")

# Define variables
counties = r"C:\data\TemplateData.gdb\USA\counties"
dissolve_fields = "STATE_NAME;STATE_FIPS"
calculate_fields= "POP1990 SUM"

# Execute Production Dissolve
arcpy.ProductionDissolve_production(counties, dissolve_fields, calculate_fields, 'FIRST', 'MULTI_PART', 'DISSOLVE_LINES')

# Check in Production Mapping license
arcpy.CheckInExtension("Foundation")

Environments

• Scratch Workspace
• Current Workspace

Licensing information

• Basic: No
• Standard: Requires Production Mapping
• Advanced: Requires Production Mapping