A viewshed shows the areas that are visible (or invisible) from a particular XY point (the "transmitter"). You can select the view area you wish to sample (radius, start and sweep angle), set the transmitter and receiver heights and include any obstructions, and choose to show visible areas or invisible areas. Viewshed analysis is useful in many applications, such as determining if mining operations or drill rigs can be viewed from public locations, determining what is visible from trails or roads, and to locate communication towers.
To create a viewshed, all you need is a grid file. Create any 2D map type from the grid (e.g. Home | New Map | Contour Map), then select the map and click Map | Add to Map | Layer | Viewshed and click on the map where you want the transmitter or origin location to be. A Viewshed layer is added to the Contents window and the visible areas from that transmitter location are shaded in green. You can select the viewshed layer in the Contents window and edit properties, including the transmitter location, in the Properties window.
A viewshed layer applied to the Diablo.grd Sample file. The red symbol designates the transmitter point, and all green areas are visible from that transmitter point.
We have some other resources to help explain viewsheds:
- Surfer 13 New Feature Series: Viewshed Maps
- Create a viewshed map in Surfer
- Join two DEM files and create a viewshed over both in Surfer
- Do Surfer viewsheds account for the curvature of the earth?
Updated October 27, 2021