Understanding the ZTV

The Zone of Theoretical Visibility (ZTV) tool in VU.CITY is a powerful feature used for assessing the visibility of proposed buildings within an urban environment. Once the analysis is complete, users receive a notification and can immediately view the results. Here’s a guide to understanding how to read and interpret the ZTV analysis.

• ZTV

  

Notification and viewing

When the ZTV analysis finishes, users are prompted with a “View Now” notification. Upon viewing, the tool displays a detailed map with various elements that signify different visibility aspects.

Legend and height bands

The legend within the ZTV tool displays ten height bands, each representing a level of the building’s height from the base (Above Ordnance Datum - AOD, or “above sea level”). These bands help in understanding the visibility from different heights of the building.

Colour-coded sample points

The map will show colour-coded square sample points scattered across the terrain. Each colour represents the lowest height band visible from the center of that point under clear theoretical conditions. It assumes visibility of higher bands from that point unless obstructed.

Theoretical visibility

The term “theoretical visibility” used here implies that the analysis does not account for situational obstacles like standing in an archway where only certain parts of the building are visible. The analysis assumes an unobstructed line of sight.

• Visibility and Tools Icons

  

‘i’ icon: Provides information about the sample size and area.

Eye icon: Enables toggling the ZTV analysis visibility on or off.

Bin icon: Allows users to delete the ZTV analysis.

Additional specifications

Sample area: The maximum area for sample points is 2,000m².

Sample point distance: The minimum distance between sample points within the sample area is 1m.

Height bands: There are ten fixed height bands calculated on a model.

Exclusions: The analysis does not include tree coverage but does include consented schemes on the timeline if activated beforehand.

Model compatibility: Primarily designed for use with models created in VU.CITY, though there is some reported success with optimally prepared imported models.

Export and timing: Results can be exported using the Screenshot feature and typically return in less than a minute on coarse output settings.