viewshed analysis

Visible field analysis is an analysis method for calculating visible fields and non-visible fields within a specified range based on observation points and their attributes (position, orientation, observation radius, etc.) in a three-dimensional scene. The visible view is the set of all visible points within the specified range based on the observation point, and the invisible view is the set of all invisible points within the specified range based on the observation point, which can be identified by different colors.

Visibility analysis can be widely used in planning sightseeing routes, setting security monitoring points, setting disaster monitoring points, avoiding detection radar blind areas and so on.

Operating steps

  1. Click 3D Analysis - Viewshed Analysis to switch to the Viewshed Analysis Settings panel.

  2. Click the Analysis button, the first point selected by the left mouse button in the 3D scene is the observation point, and then move the mouse to set the viewing distance. After selecting the distance, click the left mouse button to determine the scope of viewing analysis.
  3. Once the visibility range is determined, the analysis results are displayed in real-time and observer information (longitude, latitude, and elevation) is displayed in the dashboard.
  4. Parameters can be set in the panel to change the analysis results and results display mode. Specific parameters include:
    • Additional height: unit is meters, default value is 1.8, used to simulate the height of people or objects, can be changed by entering a value in the text box or moving the slider, the value range is [0.0, 10.0].
    • Viewable angle: unit is degrees, default value is 90, used to simulate human angle of view, can be changed by entering a value in the text box or moving the slider, value range is [0,180].
    • Line of sight: used to represent each line of sight. After the analysis is complete, the color and transparency (RGBA) can be changed in the pop-up Color Settings panel by checking the checkbox to open and clicking the Color box.
    • Visible volume: used to represent the visible area. After the analysis is complete, the color and transparency (RGBA) can be changed in the pop-up Color Settings panel by checking the checkbox to open and clicking the Color box.
    • Non-visible volume: Used to represent an invisible area. After the analysis is complete, the color and transparency (RGBA) can be changed in the pop-up Color Settings panel by checking the checkbox to open and clicking the Color box.
  5. The visibility analysis results are shown in the figure below. The green area is the visible area, and the red area is the invisible area.

  6. Click Clear to clear the 3D scene of through-view analysis results.