ViewshedAnalysis

A spatial analysis object for viewshed analysis, used to perform viewshed analysis on a 3D scene.

Constructor

import { ViewshedAnalysis } from '@maptalks/gl-layers';

const viewshedAnalysis = new ViewshedAnalysis({
  eyePos: [121, 39, 100],
  lookPoint: [121, 39, 0],
  verticalAngle: 90,
  horizontalAngle: 90,
  visibleColor: [0.0, 1.0, 0.0, 1.0],
  invisibleColor: [1.0, 0.0, 0.0, 1.0]
});

viewshedAnalysis.addTo(groupGLLayer);

Details

Parameters:

• options* Object configuration options, the available options are as follows:

Option	Type	Description	Default
eyePos*	Number[]	Observer position, [x, y, h]; x and y are longitude and latitude, h is altitude	null
lookPoint*	Number[]	Look-at target position, [x, y, h]; x and y are longitude and latitude, h is altitude	null
verticalAngle	Number	Vertical angle of view, in degrees	90
horizontalAngle	Number	Horizontal angle of view, in degrees	90
visibleColor	Number[]	A 4-component normalized array; the color of the visible area	[0, 1, 0, 0.3]
invisibleColor	Number[]	A 4-component normalized array; the color of the invisible area	[1, 0, 0, 0.3]

Note: The default opacity of visibleColor / invisibleColor has been adjusted to 0.3 in the new version (default values [0.0, 1.0, 0.0, 0.3] / [1.0, 0.0, 0.0, 0.3] in the 2026 source's renderAnalysis, verified 2026).

Methods

getVertexCoordinates()

Gets the coordinates of the 4 vertices of the viewshed pyramid (added after cross-checking the 2026 source code).

Returns:

• Array

Methods Inherited from Analysis

addTo(groupGLLayer)

Adds the analysis object to a GroupGLLayer.

Spatial analysis objects can only be added to a GroupGLLayer; they cannot be added to other WebGL layers.

Parameters:

• groupGLLayer GroupGLLayer the GroupGLLayer

Returns:

• this

remove()

Removes the spatial analysis object from the layer.

Returns:

• void

update(name, value)

Updates options data.

Parameters:

• name String the setting name
• value any the setting value

Returns:

• void

getAnalysisType()

Gets the type of the Analysis.

Returns:

• String

getDefines()

Internal method.

Returns the defines added to the shader when the Analysis is rendered.

Returns:

• Object

renderAnalysis(meshes)

Internal method.

Renders the spatial analysis scene (implemented by each analysis subclass) and returns the uniform variables required for rendering.

Parameters:

• meshes Mesh[] the scene meshes

Returns:

• Object

enable()

Enables the analysis.

Returns:

• void

disable()

Disables the analysis.

Returns:

• void

isEnable()

Whether the analysis is enabled.

Returns:

• Boolean

getExcludeLayers()

Gets the list of layer ids excluded from the analysis (these layers are ignored during the analysis).

Returns:

• String[]

setExcludeLayers(layerIds)

Sets the list of layer ids excluded from the analysis.

Parameters:

• layerIds String[] list of layer ids

Returns:

• void

exportAnalysisMap(meshes)

Exports the analysis result image (RGBA pixel data); returns null when the analysis is not enabled.

Parameters:

• meshes Mesh[] the scene meshes

Returns:

• Uint8Array

This document has been cross-checked against the @maptalks/gl-layers 2026 source (api-notes-others.md / api-notes-vt-gl.md)