A skyline analysis provides understanding of the shape of the horizon from one or more viewpoints. The horizon can include surfaces and features, like buildings, combined to understand the physical environment.
Urban planners, for example, need to assess the visual impact of development projects on the surrounding environment. By analyzing the visibility of proposed structures or infrastructure from various viewpoints, planners can evaluate potential visual obstructions, minimize impacts on scenic landscapes, and maintain the aesthetic integrity of an area. Mission planners can use skyline analysis to identify areas of strategic advantage or vulnerability by analyzing the visibility from potential observation posts.
Workflows
You can assess the skyline interactively in ArcGIS or use the geoprocessing tools in 3D Analyst extension to create skyline features and derive quantitative measurements.
Visual skyline assessment
You can understand the skyline from one or more viewpoints by creating a scene in ArcGIS Pro or Scene Viewer that represents your area of interest and then navigate interactively to specific locations. You can also use bookmarks (called slides in Scene Viewer) to go to a particular geographic location. Once you are at a specific location, you can look around to assess the skyline around you and see which areas are visible or not. Next, you can, for example, turn on or off a layer that represents a new property development to understand the visual impact on the skyline.
In addition, Experience Builder allows you to do a visual comparative analysis of two or more scenes. As you navigate in one scene, the camera position and angle are updated in all scenes at the same time.
Skyline analysis
When your workflow requires qualitative and quantitative measurements, use the skyline geoprocessing tools in 3D Analyst extension. The Skyline, Skyline Barrier, and Skyline Graph geoprocessing tools, when run sequentially, can help you conduct a full skyline analysis.
The Skyline geoprocessing tool generates a 3D polyline representation of the line separating the sky from the surface and features surrounding each observer point. The Skyline Barrier geoprocessing tool generates height control surfaces from skylines. The barriers are useful for urban planning scenarios because they can be used to identify whether a proposed building will impact the skyline. They can also be used to test the proximity of features to the horizon.
To derive quantitative measurements from a skyline analysis, use the Skyline Graph geoprocessing tool. The Skyline Graph geoprocessing tool calculates the sky visibility ratio and generates an optional table and a polar graph.
Together, the Skyline Analysis tools can be used to understand how much sky can be seen from an observer point and assess the possible obstructions for that location.
Considerations
The skyline analysis tools require that input data is in a projected coordinate system. An input feature class that is not in a projected coordinate system can be reprojected using the Project geoprocessing tool, and an input raster surface can be reprojected using the Project Raster geoprocessing tool.
This Skyline geoprocessing tool can also be used to create feature silhouettes that can be extruded into volumes using the Skyline Barrier geoprocessing tool. These volumes describe the spaces that cannot be seen from the observer point.
Required software
ArcGIS Pro, ArcGIS Earth, CityEngine, and applications built with the Maps SDK for JavaScript such as Scene Viewer, Instant Apps, and Experience Builder can be used to do visual assessments of a skyline. You will need ArcGIS Pro with 3D Analyst to analyze skylines and persist the results in a geodatabase. An ArcGIS Online or ArcGIS Enterprise account is required to publish and share the analysis layers as a 3D scene service across your organization.
Explore the following resources to learn more about conducting a skyline analysis in ArcGIS.
ArcGIS help documentation
Reference material for ArcGIS Pro:
- 3D navigation in ArcGIS Pro
- Navigation in Scene Viewer
- Navigation in CityEngine
- Navigation in ArcGIS Earth
- Bookmarks in ArcGIS Pro
- Slides in Scene Viewer
- Bookmarks in ArcGIS Earth
- Basics of a skyline analysis
- How the Skyline geoprocessing tool works
- How the Skyline Barrier geoprocessing tool works
- How the Skyline Graph geoprocessing tool works
- 3D Analyst extension
ArcGIS blogs, stories, and technical papers
Supplemental guidance about concepts, software functionality, and workflows:
Esri community
Online places for the Esri community to connect, collaborate, and share experiences:
- Ask the 3D community questions.