Thin Road Network (Cartography)


Generates a simplified road network that retains connectivity and general character to display at a smaller scale.

This tool does not generate new output. It assign values in the Invisibility Field in the input feature classes to identify features that are extraneous and can be removed from view to result in a simplified, yet representative, collection of roads. No feature geometry is altered or deleted.

Features are not actually deleted by Thin Road Network. To actually remove features, consider using the Trim Line tool.

The resulting simplified road collection is determined by feature significance, importance, and density. Segments that participate in very long itineraries across the extent of the data are more significant than those required only for local travel. Road classification, or importance, is specified by the Hierarchy Field parameter. The density of the resulting street network is determined by the Minimum Length parameter which corresponds to the shortest segment that is visually sensible to show at scale.

Learn more about How Thin Road Network works and see a table of recommended minimum length values to use as a starting point.


A warning is raised if the input features are not in a projected coordinate system. This tool relies on linear distance units, which will create unexpected results in an unprojected coordinate system . It is strongly suggested that you run this tool on data in a projected coordinate system to ensure valid results. An error is raised and the tool will not process if the coordinate system is missing or unknown.


Thin Road Network tool
The Thin Road Network tool simplifies a collection of roads while retaining character and connectivity.



ThinRoadNetwork_cartography (in_features, minimum_length, invisibility_field, hierarchy_field)
ParameterExplanationData Type

The input linear roads that should be thinned to create a simplified collection for display at smaller scales.

Feature Layer

An indication of the shortest road segment that is sensible to display at the output scale. This controls the resolution, or density, of the resulting road collection. If the units are in point, mm, cm, or inches the value is considered in page units and the reference scale is taken into account.

Linear Unit

The field that stores the results of the tool. Features that participate in the resulting simplified road collection have a value of 0 (zero). Those that are extraneous have a value of 1. A layer definition query can be used to display the resulting road collection. This field must be present and named the same for each input feature class.


The field that contains hierarchical ranking of feature importance, where 1 is very important and larger integers reflect decreasing importance. A value of 0 forces the feature to remain visible in the output collection. This field must be present and named the same for each input feature class.


Code Sample

ThinRoadNetwork tool Example (Python Window)

The following Python Window script demonstrates how to use the ThinRoadNetwork tool in immediate mode.

import arcpy
from arcpy import env
env.workspace = "C:/data/cartography.gdb/transportation"
arcpy.ThinRoadNetwork_cartography("roads.lyr", "1000 meters", "invisible", "level")
ThinRoadNetwork tool Example (stand-alone Python script)

This stand-alone script shows an example of using the ThinRoadNetwork tool.

# Name:
# Description:  Removes a subset of road segments to create a simplified road network that retains the connectivity and character of the input.
# Import system modules
import arcpy
from arcpy import env

# Set environment settings
env.workspace = "C:/data/cartography.gdb/transportation"

# Set local variables
in_features = "roads.lyr"
minimum_length = "1000 meters"
invisibility_field = "invisible"
level_field = "level"

# Execute Thin Road Network
arcpy.ThinRoadNetwork_cartography(in_features, minimum_length, invisibility_field, level_field)


Reference Scale

The reference scale is only considered when the Minimum Distance parameter is entered in page units. When the reference scale is available, the detection of false dead ends is based on feature separation of 0.5mm at scale. Otherwise a value twice the tolerance of the spatial reference is used.

Related Topics

Licensing Information

ArcView: No
ArcEditor: No
ArcInfo: Yes