April 2, 2024
How to Display Sun Angle and Multi-Directional Hill Shading in GIS
The Dynamic Hill Shading tool in Global Mapper displays directional shadows on terrain data to simulate how light and shadow might fall on that surface. Sometimes referred to as shaded relief, hill shading is useful for enhancing the visualization of terrain texture, estimating shadow location, and more.
Compare a terrain layer shaded to display elevation values against the same layer with the default hill shading enabled.
In Global Mapper, hill shading is a simple visualization technique that applies a UI shading element to raster elevation data. It does not alter elevation values, only how they are displayed in the 2D and 3D views. This blog describes two methods that can be achieved using the Dynamic Hill Shading tool. Both can be used to create slope-enhanced shaded relief maps, although they differ in function:
- Real World Hill Shading uses the data’s location and a specified time and date to display the sun’s angle, creating lighting and shadows to represent reality.
- Multidirectional Hill Shading is an artificial visualization technique that uses multiple light sources to enhance the data’s texture and detail.
Slide to compare a multidirectional hillshade, to a real-world hill shade calculated for 1:00 pm in Nebraska during March.
The applied hillshade can be further customized using these and other settings provided in the Dynamic Hill Shading tool:
| Vertical Exaggeration incrementally changes how the Z value, or elevation, is displayed in the 2D View. This works similarly to exaggeration in the 3D view. Increasing the vertical exaggeration gives a rougher-looking terrain with deeper shadows. This setting is managed in the Dynamic Hillshade tool for 2D, and in Configuration > 3D View Properties > Environment for the 3D View.
Terrain Shaders are built-in and customizable options for showing variation in elevation through the use of color. These options match those available in the Viewer Toolbar.
Color Elevations Based on Visible Elevation Values adjusts the terrain shader colors to interpret only the elevation values visible in the main 2D view. Colors will change as you zoom in and out, or pan around the data. |
Required data: A terrain raster layer. Find this through Global Mapper’s Online Data tool, or import your own file.
Real World Hill Shading
Global Mapper version 25.1 includes an enhancement to the Dynamic Hill Shading tool, the option to calculate the sun’s Azimuth and Altitude based on the time at a specified location. The goal of this type of hill shading is to accurately model natural lighting over terrain. This tool gives users the power to visualize which areas will receive sunlight throughout the day at any point during the year.
To use this method, from the left side of the Dynamic Hill Shading dialog choose a date and time to be used in calculating the sun’s location for display in the 2D and 3D workspaces automatically. Click Calculate Sun Angle to see these changes applied to the data. Global Mapper will display a warning if the chosen time is before or after the scheduled sunrise. The date and time settings are automatically localized to the data’s location; no worries about taking time changes into account!
Multidirectional Hillshade
Multidirectional hill shading is a data visualization technique that uses multiple suns to highlight details in the terrain. This method is great for displaying all crevices across the landscape or enhancing certain characteristics. These highly detailed maps that visualize data in an eye-catching way are commonly used in creative map making and can be easily generated in Global Mapper.
In the Dynamic Hill Shading tool, check the Use Multiple Light Sources box to enable somewhere between 4-6 sources. These separate light sources will add shadows to steep sections of the terrain without obscuring crevices and other surrounding areas. Use the Light Direction gimbal to adjust the sun’s locations to better fit your data. When one sun is adjusted, the others will match automatically to maintain even spacing. Typically, bringing the sun’s closer to the center will provide a more focused light for highlighting small details. Pulling the sun’s further out will create a softer appearance.
Data visualization methods in Global Mapper, such as hillshading, can be exported through a simple screenshot, or customized with the creation of a Map Layout. For more information on creating map layouts, check out this YouTube video: Map Publishing in Global Mapper.
Try the Dynamic Hill Shading in Global Mapper with a free 14-day trial today! If you have any questions, please contact us!
