Sight lines
Sight lines describe what you can see from a given point, typically from a property or a planned building. For housing projects, the view is one of the strongest value drivers, especially towards water, fjord and mountains, and a good sight analysis gives the developer and the agent a clear picture of what future residents will actually see.
Professionally, the term is used in two quite different traditions. In transport, sight requirements at junctions, accesses and sight-line zones are a design parameter under the Norwegian Public Roads Administration's handbook N100 Veg- og gateutforming (road and street design), based on the speed limit and stopping sight distance. The road authority can require sight-line zones to be secured as a hensynssone (consideration zone) in a zoning plan. In land use planning, sight analyses are used to document the distant visual impact of new buildings, the effect on cultural environments and protected silhouettes, and the preservation of established view corridors in the urban landscape.
The calculation is usually made through a GIS-based viewshed analysis, where lines of sight are projected against a digital terrain model (DTM) and a digital surface model (DSM) that also captures existing buildings and vegetation. The data comes from Kartverket's national elevation model, built on airborne laser scanning with a point density down to five points per square metre in built-up areas, and is distributed through Geonorge under the Norwegian Licence for Open Government Data (NLOD).
The result is used for volume studies early in a feasibility study, to document overlooking and sunlight conditions towards neighbours in a building application, and it is regularly included as an appendix to zoning plans along with sun and shadow diagrams. Remember that a sight analysis has a short shelf life: new buildings on a neighbouring property can block the view, so it is important to analyse the zoning plan, permitted heights and the development potential of neighbouring properties when you value the view in a project.
In Placepoint you can analyse sight lines from different height levels on a property as part of a 3D volume study, so that the developer, the agent and the buyer all get a clear picture of what will be visible from a planned building.
How it looks in Placepoint
In Placepoint you find this in the 3D Designer:
From Placepoint's dictionary: Sight lines
More information: Kartverket: Elevation data, Geonorge: National elevation model, Statens vegvesen: Handbooks
English: Sight lines (view-corridor analysis from a building or vantage point).
Frequently asked questions
What are sight lines in a property context?
Sight lines show what you can see from a given position or property. The view and sight conditions have a large effect on property value, especially for homes with a fjord, sea or mountain view.
How can I analyse sight lines in Placepoint?
In Placepoint you can use the Line of Sight tool to simulate the view from different height levels on a property. This gives a clear picture of the view future residents will have.
How does the view affect property value?
The view is one of the strongest value drivers for homes, especially towards water, fjord and mountains. Analyses show that a significant view can increase the value of a home noticeably compared with similar homes without a view.
Can new buildings block my view?
A neighbouring property can be built up and block the view. It is important to analyse the zoning plan, permitted heights and the development potential of neighbouring properties to assess the risk of losing the view.
How are sight lines calculated?
Sight lines are calculated through GIS-based terrain analysis (viewshed analysis) that takes the terrain and existing buildings into account. Placepoint offers this as an interactive tool directly in the map.