Hello, please help me address this flaw in my visibility analysis workflow.
I’m running a visibility/viewshed analysis in ArcGIS Pro for a visual impact assessment and am trying to model the following real-world condition:
I need visibility to be modeled from human eye height (~5.5 feet above ground level), while simultaneously screening views by including intervening trees and buildings that may block visibility.
The problem that I am running into is that the Visibility tool only accepts a single surface which is used for both viewer elevations and obstructions.
In an ideal world, I want the viewer elevation to pull from the Bare Earth Digital Elevation Model (DEM) surface, while my Digital Surface Model (DSM) that captures buildings and vegetation is used for all of the intervening areas between each viewer point and the project.
Viewer elevation = DEM + eye height
Obstructions = DSM
In my current methodology, I run the Visibility tool twice:
My question:
Is there a better way in ArcGIS Pro to model ground-level viewers (DEM + eye height) while using a DSM to represent intervening obstructions, ideally in a single analysis step?
I’m curious whether anyone has solved this. Any advice or references would be greatly appreciated!! Thank you.
Hi @LeahCharash
You could try the following:
1. Create an observer-only raster
- Create your observer points to raster
- Use a small cell size (same as DEM/DSM)
- Assign each observer cell a value DEM +1.7m
2. Merge this with the DSM and use the Raster Calculator
Con(IsNull(observer_raster), DSM, observer_raster)
This should produce a single surface where:
- At observer locations > elevation = DEM + eye height
- Everywhere else > Elevation = DSM (trees and buildings)
3. Run the Viewshed on the hybrid layer
I hope this helps in some way.