Symbolize by Dot Density (Business Analyst)
Summary
Thematically maps a feature class based on a numeric field as dots on the map to convey the intensity of an attribute.
Usage
-
This is a type of thematic map in which a certain number of dots are used to represent a numeric attribute associated with a polygon layer.
-
When selecting the dot size, keep a perspective on the data you are symbolizing. For example, selecting a dot size of 10 based on 2004 total population per county would result in a map that would be mostly black, since the dot distribution would be too dense to visualize. A better choice would be to select a dot size of 100 or 1,000 to better see the distribution of population.
-
The dots are evenly distributed across each polygon in your feature class.
Syntax
| Parameter | Explanation | Data Type |
InputFeatureLayer |
The input feature layer. | Feature Layer |
Field |
The attribute field used to define the thematic map. | String |
DotSizeParameterName |
The numeric value that represents the field selection to be symbolized. | Double |
ColorParameterName |
The color assigned to the points to be symbolized. | Long |
UseSelectedFeatures (Optional) |
Identifies the features that will be used to generate the thematic map.
| Boolean |
Code Sample
# Name: SymbolizeByDotDensity.py
# Description: Symbolizes block groups by dot density using total population.
# Author: ESRI
# Import system modules
import arcpy
arcpy.ImportToolbox("C:\Program Files\ArcGIS\Desktop10.0\ArcToolbox\Toolboxes\Business Analyst Tools.tbx")
try:
# Acquire extension license
arcpy.CheckOutExtension("Business")
# Defines the parameters for the Symbolize by Dot Density tool
Input = "C:/Program Files/ArcGIS/Desktop10.0/Business Analyst/Data/BDS/esri_bg.bds"
Fld= "TOTPOP_CY"
# Thematically symbolizes a polygon layer by dot density
# Red point is –65536
arcpy.SymbolizeByDotDensity_ba(sInput, sFld, 10, –65536)
# Release extension license
arcpy.CheckInExtension("Business")
except:
print arcpy.GetMessages(2)