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Show a line of sight between two moving objects.

Image of line of sight geoelement

Use case

A line of sight between GeoElements (i.e. observer and target) will not remain constant whilst one or both are on the move.

A GeoElementLineOfSight is therefore useful in cases where visibility between two GeoElements requires monitoring over a period of time in a partially obstructed field of view (such as buildings in a city).

How to use the sample

A line of sight will display between a point on the Empire State Building (observer) and a taxi (target). The taxi will drive around a block and the line of sight should automatically update. The taxi will be highlighted when it is visible. You can change the observer height with the slider to see how it affects the target’s visibility.

How it works

  1. Instantiate an AnalysisOverlay and add it to the SceneView’s analysis overlays collection.
  2. Instantiate a GeoElementLineOfSight, passing in observer and target GeoElements (features or graphics). Add the line of sight to the analysis overlay’s analyses collection.
  3. To get the target visibility when it changes, react to the target visibility changing on the GeoElementLineOfSight instance.

Relevant API

  • AnalysisOverlay
  • GeoElementLineOfSight
  • LineOfSight.getTargetVisibility

Tags

3D, line of sight, visibility, visibility analysis

Sample Code

module-info.java module-info.java LineOfSightGeoElementSample.java
/*
* Copyright 2022 Esri.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
module com.esri.samples.line_of_sight_geoelement {
// require ArcGIS Maps SDK for Java module
requires com.esri.arcgisruntime;
// handle SLF4J http://www.slf4j.org/codes.html#StaticLoggerBinder
requires org.slf4j.nop;
// require JavaFX modules that the application uses
requires javafx.graphics;
requires javafx.controls;
exports com.esri.samples.line_of_sight_geoelement;
}