Instructions for use

3D Viewshed Analysis is to analyze the set of all viewshed points in the area based on a certain horizontal perspective, vertical perspective and Specify Range radius relative to a certain observation point on the Model Data surface of the scene. Analyst Result has green areas that are visible at the observation point and red areas that are not visible at the observation point.

Application scenario

Visual analysis can be widely used in security, monitoring, deep forest fire observation platform settings, navigation, aviation, military and other aspects.

Operation steps

Add data
1. to the scene for Viewshed Analysis.
2. On the 3D Analysis tab, in the Spatial Analysis group, click the button to bring up the 3D Spatial Analysis "panel.
3. When the mouse is attached to the red dot, you can click on the Model Data surface to select the observation point and move the mouse to set the viewfield distance to determine the scope of the Viewshed Analysis.
After
4. determining the observation point and visual distance of Viewshed Analysis, you can continue to add Viewshed Analysis in the 3D Spatial Analysis "toolbar. Or Add , Delete , Import , Export , Save Analysis Results, and Obstacle Points and Sight Lines.
5. 3D Viewshed Analysis can set Viewer Info, including position, additional height, azimuth, pitch angle and visual distance. One or more results can be selected in the Analyst Result list for setting:
   • View Position: Enter the coordinate values of the observation point in the X, Y, and Z text boxes respectively to modify the position of the observation point.
   • Additional Height: The additional height can be approximately regarded as the height of a person. Add a height value in the additional height text box to modify the position of the observation point. The default is 1.8 meters.
   • Azimuth (degrees): The angle between the direction of the Current Camera and the direction of true north. Directly input the azimuth angle, and the azimuth angle supports any angle value.
   • Pitch Angle (deg): The angle between the current analyzed camera orientation and the ground plane. You can directly input the pitch angle to adjust the pitch angle of Viewshed Analysis.
   • Visual Distance (Meters): used to set the length range of Viewshed Analysis, in meters. The Viewshed Analysis range can be adjusted by directly entering the visual distance.
6. In the Parameter Settings area, you can set the Analyst Result Parameters, including horizontal viewing angle, vertical viewing angle, visible area color, invisible area color, and analysis precision:
   • Horizontal angle of view (degrees): used to set the horizontal range of Viewshed Analysis. The default value is 90 degrees.
   • Vertical viewing angle (degrees): used to set the Analysis Bounds of the vertical direction of the Viewshed Analysis. The default value is 60 degrees.
   • Visible/Invisible Area Color: Click the Drop-down Button on the right of "Visible Area Color" or "Invisible Area Color" to reset the colors of visible and invisible areas.
   • Prompt Line Color: Click the Drop-down Button on the right of "Prompt Line Color" to reset the color and transparency of the prompt line. The prompt line is the scope of the field of view.
   • Analysis Precision: Set the quality level of Analyst Result, including low level, medium level and high level.
   • Viewport: used to display the Viewshed Analysis in the First View. The viewport cannot be changed.
In the
7. toolbar area, operations such as add, delete, import, export of observation points, Save Analysis Results, Save barrier point and barrier line are provided.
Description of toolbar buttons
• Button: You can click the mouse to determine the location of the observation point, and move the mouse to click again to determine the radius of the Viewshed Analysis area.
• Button to remove the Viewshed Analysis record selected in the panel.
• Button: used to import 3D Point Dataset as observation point, set Parameters, and perform Viewshed Analysis. The parameters in the Import View Point "dialog are as follows:

  Datasource: Datasource where the observation point data to be imported is located.

  Dataset: Dataset where the observation point data is located.

  Name: Observation Point Data Name.

  Bearing: select the bearing field, or directly enter the bearing value. The angle range is: -180 to 180 degrees.

  Pitch Angle: select the field where the pitch angle is located, or directly input the pitch angle value, the angle range is: -90 to 90 degrees.

  Visual distance: select the field of visual distance, or directly input the distance value in meter.

• Button: Export as Point dataset of observation points recorded by Viewshed Analysis, and select Fields to save in the attribute table, where azimuth, pitch angle and visual distance can be set.

  The specific parameters are as follows:

  Datasource: Datasource where the observation point data to be exported is located.

  Dataset: The saved name of the Export View PointDataset.

  Name: Check "Name" to export its name information, and set to save Field.

  Azimuth: Check "Azimuth" to export its angle information, and set to save Field.

  Pitch Angle: Check "Pitch Angle" to export its angle information, and set to save Field.

  Visual distance: Check "Visual distance" to export the visual distance information, and set and save Field.

• Button: Save the result of Viewshed Analysis. In the pop-up dialog box, you can set the Datasource for storing the result and the exported Result Data category.

  The specific parameters are as follows:

  Datasource: Target Datasource saved by Analyst Result.

  Visible body: Select the "Visible body" check box to save the visible area in the viewport. The Dataset Name can be customized in the input box.

  HiddenBody: Select the "HiddenBody" check box to save the invisible area in the viewport. You can customize the Dataset Name in the input box.

  Visible Surface: Select the Visible Surface "check box to save the surface of the visible area in the viewport. You can customize the Dataset Name in the input box.

  Line of sight: Select the "Line of sight" check box to save the Line of sight Dataset in the Analyst Result of the field of view. The Dataset Name can be customized in the input box.

  Obstacle Point: Select the "Obstacle Point" check box to save the Obstacle Point Dataset in the View Analyst Result. The Dataset Name can be customized in the input box.

  Observation Point: Select the "Observation Point" check box to save the Observation Point Dataset in the View Analyst Result. You can customize the Dataset Name in the input box.

The effect picture
8. of Viewshed Analysis is as follows, in which the red range is the invisible area and the green range is the visible area.

   Figure: Viewshed Analysis rendering

9. Check the HighLight Show Visible Body "on the 3D Spatial Analysis" panel, the visible model will be highlighted in the scene, and the Open attribute table will be automatically associated. Displays the Attributes of the visible model.