Disperse Markers (Cartography)

Summary

Finds point symbols that overlap or are too close to one another based on symbology at reference scale and spreads them apart based on a minimum spacing and dispersal pattern.

Illustration

Points that are clustered within a specified distance are dispersed in the pattern selected.

Usage

• The input must be a symbolized point feature layer. Multipoint features are not a valid input. The input feature class is changed by this tool.

• This tool operates by assessing proximity of symbolized point features. The symbology extent and the reference scale are considered in conjunction with one another. Run this tool only after you finalize the appearance of the symbols, and ensure that the reference scale corresponds to the final intended output scale.

• Clustered or coincident point symbols are assessed and processed in groups. The analysis of marker groups is based on a minimum rectangular envelope around each marker. Groups are composed of markers with envelopes that overlap or are within the minimum spacing of others. In each group, markers are dispersed to the minimum spacing.

• Graphical overlaps may be introduced between point groups. Use the Detect Graphic Conflict tool to identify conflicts.

Parameters

Dialog

Label	Explanation	Data Type
Input Point Features	The input point feature layer to be dispersed.	Layer
Minimum Spacing	The minimum separation distance between individual point symbols in page units. A distance must be specified and must be greater than or equal to zero. When a positive value is specified, markers will be separated by that value; when a value of zero is specified, point symbols will touch. The default page unit is Points.	Linear Unit
Dispersal Pattern (Optional)	Specifies the pattern that will be used to place the dispersed point symbols. A group of point symbols will have a center of mass derived from the locations of all points in the group. The center of mass is used as the anchor point around which the dispersal pattern operates. Expanded—The general pattern of the point symbols will be maintained as they are spread apart. Points that were exactly coincident will be dispersed to a circle around their center of mass. This is the default. Random—Point symbols will be placed around the center of mass in a random dispersal that respects the minimum spacing. Squares—Point symbols will be placed in multiple square rings around the center of mass, ensuring that all points are placed as closely together as allowable by the minimum spacing parameter. Rings—Point symbols will be placed in multiple circular rings around the center of mass, ensuring that all points are placed as closely together as allowable by the minimum spacing parameter. Square—Point symbols will be placed evenly around the center of mass in a single square pattern. Ring—Point symbols will be placed evenly around the center of mass in a single circular pattern. Cross—Point symbols will be spaced evenly on horizontal and vertical axes originating from the center of mass. X-cross—Point symbols will be spaced evenly on 45° axes originating from the center of mass. Column—Point symbols will be spaced evenly on a vertical axis originating from the center of mass. Row—Point symbols will be spaced evenly on a horizontal axis originating from the center of mass.	String

Derived Output

Label	Explanation	Data Type
Updated Input Features	The updated input features.	Feature Layer

Python

arcpy.cartography.DisperseMarkers(in_point_features, minimum_spacing, {dispersal_pattern})

Name	Explanation	Data Type
in_point_features	The input point feature layer to be dispersed.	Layer
minimum_spacing	The minimum separation distance between individual point symbols in page units. A distance must be specified and must be greater than or equal to zero. When a positive value is specified, markers will be separated by that value; when a value of zero is specified, point symbols will touch. The default page unit is Points.	Linear Unit
dispersal_pattern (Optional)	Specifies the pattern that will be used to place the dispersed point symbols. A group of point symbols will have a center of mass derived from the locations of all points in the group. The center of mass is used as the anchor point around which the dispersal pattern operates. EXPANDED—The general pattern of the point symbols will be maintained as they are spread apart. Points that were exactly coincident will be dispersed to a circle around their center of mass. This is the default. RANDOM—Point symbols will be placed around the center of mass in a random dispersal that respects the minimum spacing. SQUARES—Point symbols will be placed in multiple square rings around the center of mass, ensuring that all points are placed as closely together as allowable by the minimum spacing parameter. RINGS—Point symbols will be placed in multiple circular rings around the center of mass, ensuring that all points are placed as closely together as allowable by the minimum spacing parameter. SQUARE—Point symbols will be placed evenly around the center of mass in a single square pattern. RING—Point symbols will be placed evenly around the center of mass in a single circular pattern. CROSS—Point symbols will be spaced evenly on horizontal and vertical axes originating from the center of mass. X_CROSS—Point symbols will be spaced evenly on 45° axes originating from the center of mass. COLUMN—Point symbols will be spaced evenly on a vertical axis originating from the center of mass. ROW—Point symbols will be spaced evenly on a horizontal axis originating from the center of mass.	String

Derived Output

Name	Explanation	Data Type
out_representations	The updated input features.	Feature Layer

Code sample

DisperseMarkers example 1 (Python window)

The following Python window script demonstrates how to use the DisperseMarkers function in immediate mode.

import arcpy
arcpy.env.workspace = "C:/data"
arcpy.env.referenceScale = "50000"
arcpy.cartography.DisperseMarkers("crime.lyr", "2 Points", "EXPANDED")

DisperseMarkers example 2 (stand-alone script)

This stand-alone script shows an example of using the DisperseMarkers function.

# Name: DisperseMarkers_standalone_script.py
# Description: Finds point symbols that are overlapping or too close to one
#              another and spreads them apart based on a minimum spacing and
#              dispersal pattern

# Import system modules
import arcpy

# Set environment settings
arcpy.env.workspace = "C:/data"
arcpy.env.referenceScale = "50000"

# Set local variables
in_point_features = "crime.lyrx"
minimum_spacing = "2 Points"
dispersal_pattern = "EXPANDED"

# Execute Disperse Markers
arcpy.cartography.DisperseMarkers(in_point_features, minimum_spacing,
                                  dispersal_pattern)

Environments

Cartographic Coordinate System, Reference Scale