Visibility Analysis
Open Table of Contents ToolBox Implementation
Calculates the visibility from a set of observer points to the features of the target dataset. If the target dataset is of polyline or polygon type, the visibility to the vertices of the geometries is calculated. The result will be a point dataset (vertices of the targets). For each point the number of observers that can see the point are recorded in the attribute table. 

Inputs:

  • A point dataset (Observers). The attribute table can have a numeric field which values will indicate the offset of the observers above the terrain.
  • A point, polyline or polygon dataset (Targets). The attribute table can have a numeric field which values will indicate the offset of the targets above the terrain.
  • A surface - Raster, ESRI TIN or PolygonZ TIN
  • Options (see Line of Sight discussion)
    • Apply Earth curvature correction
    • Apply air refraction corrections
    • Apply radio wave corrections.

Outputs:

  • A point feature class
    • ET_Visible - the number of observers that can see the point
  • All attributes of the original polygons are preserved.

Notes:

  • The function is resources hungry and time consuming. Do not use it on large datasets. Recommended is O x T  < 500 where 
    • O = Number Observers 
    • T =  Number Target Points

ToolBox implementation

Command line syntax - two different toolbox tools available depending on the type of the input TIN. Check the color coding for specifics.

ETS_GPVisibilityEsriTIN <Observers Dataset> <Target Dataset> <Input TIN>  <Out Feature Class> <Observer Offset Field> <Target Offset Field> {Use Earth Curvature}  {Refraction Correction} {Radio Waves Correction} {Cutoff Distance}
ETS_GPVisibilityPolygonZTIN <Observers Dataset> <Target Dataset> <Input TIN>  <Out Feature Class> <Observer Offset Field> <Target Offset Field> {Use Earth Curvature}  {Refraction Correction} {Radio Waves Correction} {Cutoff Distance}

Parameters

Expression Explanation
<Observers Dataset> A Point feature layer or feature class
<Target Dataset> A  Point or Polyline feature layer or feature class
<Input TIN> An ESRI TIN layer or dataset
<Input TIN> A PolygonZ TIN (feature class)
<Out Feature Class> A String - the full name of the output feature class.
<Observer Offset Field> A String representing the name of the field which values are going to be used as offset of the observers above the raster.
<Target Offset Field> A String representing the name of the field which values are going to be used as offset of the target above the raster.
 {Use Earth Curvature} A Boolean
 {Refraction Correction} A Double representing the air refraction coefficient - Default value = 0.13
 {Radio Waves Correction} A Double representing the radio waves correction coefficient - Default value = 1.333333
 {Cutoff Distance} A Double representing the Cutoff distance.

Scripting syntax

ETS_GPVisibilityEsriTIN (Observers Dataset, Target Dataset, Input TIN, Out Feature Class, Observer Offset Field, Target Offset Field, Use Earth Curvature, Refraction Correction,  Radio Waves Correction, Cutoff Distance)

ETS_GPVisibilityPolygonZTIN (Observers  Dataset, Target Dataset, Input TIN, Out Feature Class, Observer Offset Field, Target Offset Field, Use Earth Curvature, Refraction Correction,  Radio Waves Correction, Cutoff Distance)

See the explanations above:
<> - required parameter
{} - optional parameter

All ESRI products mentioned are trademarks of Environmental Systems Research Institute, Inc.
Copyright: Ianko Tchoukanski