Intervisibility (3D Analyst)

Summary

Determines the visibility of sight lines using potential obstructions defined by any combination of 3D features and surfaces.

Usage

• This tool modifies the input Sight Lines parameter value by adding a new field or updating an existing field. You can specify the field name in the Visible Field Name parameter. The field value will be 1 for visible sight lines or 0 for obstructed sight lines. If you do not have write access to the input features or do not want to modify the input data, make a copy of the input to use with this tool. See Tools that do not create output datasets for more information and strategies to avoid unwanted data changes.

• Only the endpoints of the input line are used to define the observer and target. Ideally, sight lines should be straight lines composed of two vertices representing the observation point and the target location to which visibility is determined.

• Consider using the Construct Sight Lines tool if the observer location is defined by point features and the visibility target is represented by data stored in a different feature class.

• The tool will run faster if all input is in the same spatial reference since data will not have to be projected (potentially multiple times) to check for obstructions. It is beneficial for all obstructions to be in the same spatial reference; the spatial reference of the sight lines is not as important, since they are easier to project.

• You can use the Line of Sight tool to determine the position of the obstructing location for nonvisible sight lines.

Parameters

Dialog

Label	Explanation	Data Type
Sight Lines	The 3D sight lines whose visibility will be determined.	Feature Layer
Obstructions	The mesh and surface datasets that provide potential obstructions for sight lines. Obstructions can be defined by any combination of multipatch features, integrated mesh scene layers, TIN datasets, and raster surfaces.	Feature Layer; TIN Layer; Raster Layer; Mosaic Layer; Scene Layer; File
Visible Field Name (Optional)	The name of the field that will store the visibility results. A resulting value of 0 indicates that the sight line's start and end points are not visible to one another. A value of 1 indicates that the sight line's start and end points are visible to one another. The default field name is VISIBLE. If the field already exists, its values will be overwritten.	String

Derived Output

Label	Explanation	Data Type
Output Feature Class	The updated 3D sight lines.	Feature Layer

Python

arcpy.ddd.Intervisibility(sight_lines, obstructions, {visible_field})

Name	Explanation	Data Type
sight_lines	The 3D sight lines whose visibility will be determined.	Feature Layer
obstructions [obstructions,...]	The mesh and surface datasets that provide potential obstructions for sight lines. Obstructions can be defined by any combination of multipatch features, integrated mesh scene layers, TIN datasets, and raster surfaces.	Feature Layer; TIN Layer; Raster Layer; Mosaic Layer; Scene Layer; File
visible_field (Optional)	The name of the field that will store the visibility results. A resulting value of 0 indicates that the sight line's start and end points are not visible to one another. A value of 1 indicates that the sight line's start and end points are visible to one another. The default field name is VISIBLE. If the field already exists, its values will be overwritten.	String

Derived Output

Name	Explanation	Data Type
out_feature_class	The updated 3D sight lines.	Feature Layer

Code sample

Intervisibility example 1 (Python window)

The following sample demonstrates the use of this tool in the Python window:

import arcpy
arcpy.env.workspace = "C:/data"
arcpy.Intervisibility_3d("sightlines.shp", ["3dbuildings.shp", "topo_tin"], "Visibility")

Intervisibility example 2 (stand-alone script)

The following sample demonstrates the use of this tool in a stand-alone Python script:

This script demonstrates how to calculate the intervisibility of sight lines constructed from observer points and target lines using the obstructions presented by a surface and building features.

# Import system modules
import arcpy

# Set environments
arcpy.env.workspace = 'C:/data'

print("Constructing Sightlines")
arcpy.ddd.ConstructSightLines("Observers.shp", "Targets.shp", "sightlines.shp", 
                              observer_height_field='Shape.Z', target_height_field='Shape.Z')

print("Calculating Intervisibility")
arcpy.ddd.Intervisibility("Sightlines.shp", obstructions=["DTM_Tin", "data.gdb/buildings"],
                          visible_field="Visibility")

Environments

Output Coordinate System, Current Workspace, Parallel Processing Factor, Extent