Draft National Wind Farm Development Guidelines - July 2010

Always use the standard scale of 1 unit equal to 1m in real world units in producing a 3D
computer model. Ensure the model is created using a GIS datum (i.e. MGA 94), and if you
decide to shift your model, make sure you record the translation so that it is easy to bring
additional data in at a later date.
What are the limitations of this technique
Computer modelling is sometimes portrayed as a time consuming and expensive exercise
that is undertaken only for the benefit of the wider public. Often proponents overlook the
usefulness of this effective design tool.
As technologies continue to change and evolve at a high rate, it is becoming increasingly
difficult to keep track of best practice 3D modelling techniques. In order to provide an
accurate representation, the proponent should engage in a relevant expert in this field.
A 3D computer model has different limitations depending on the extent of elements
modelled. For example, if the simulation models topography and proposed turbines only, it
can be assumed that the model provides an appreciation of the potential views and the
form and massing of the proposed development, but does not provide an accurate
representation of the final outlook. To provide a more accurate picture, a higher level
output is required (such as a photomontage, 3D simulation (animation) or virtual reality
(VR) modelling).
There are potential inaccuracies in digital data (e.g. limitations of contour data) that need
to be considered.
C.7.4 Viewshed mapping
What is Viewshed Mapping
A viewshed (or ‘seen area’) is defined as the land visible from a point, or series of points. In
its most basic form, a viewshed map, or ‘zone of visual influence’ (ZVI) analysis, identifies an
area of landscape and/or object(s) that would be visible assuming that it had no
vegetation cover or built structures.
What is Viewshed Mapping used for
Viewshed mapping is undertaken early in a project to assist professionals and communities
in identifying locations from which the development will be visible, and to assist in
determining the appropriate boundaries for the study area. It is also a useful tool in the
early stages of a development proposal to identify the most useful locations for
photomontages and similar computer generated simulations.
Page 100 Draft National Wind Farm Development Guidelines – 2 July 2010