Chris McDermott, from The Landmark Practice, champions the value of photorealistic montages in landscape impact assessment
The ability to produce photorealistic montages to show how a proposed development is likely to appear within a landscape or townscape is rapidly becoming an essential tool in landscape and visual impact assessment (LVIA).
If a picture paints a thousand words, an accurate series of photomontages can tell it as it is – allowing the client, members of the public, statutory consultees and the planning authority to make their own assessment of the merits or otherwise of a scheme.
Planning officers are increasing stipulating that photomontages should be produced as part of the LVIA process for schemes that are likely to have a significant visual impact. The production of photomontages helps the assessor make a more accurate judgement and also allows the early identification of undesirable impacts that can be reduced, avoided or mitigated.
There are four key areas to get right in creating a photomontage:
1. Viewpoints
The viewpoint should be agreed with all parties beforehand. Photomontage work can be time consuming and expensive so it is important to choose the most meaningful and representative views. Often it is useful to present viewpoint photographs with simple block modelling or notation as to where the proposed development might appear in the view.
2. Accuracy
The photomontage needs to be accurate. Often an accurate three dimensional model of the development can be obtained from the architect or engineer and this is likely to become easier as building information modelling is adopted more widely.
The skill is in importing the selected viewport into the photograph at the right size and orientation and then ensuring the rendering and light effects are accurate. There are many methods to achieve this, but if done properly the level of accuracy can be very high. The best test of accuracy is to take photographs of the development once it is complete and compare it with the original photomontage.
Clearly this verification is too late to influence the original planning process, but it does give those producing the photomontages reassurance that the techniques they use do produce accurate results.
At The Landmark Practice we always check the photomontage against the built scheme and it gives staff tremendous satisfaction to see how close they can match it. Sometimes practitioners do not get it quite right but the comparison allows us to make adjustments for future work. For example, on an initial solar photovoltaic panel project we did not get the colour and intensity of the sheen of solar panels as accurate as we would have liked, but we have been able to rectify this in future projects.
Photomontages are also useful for demonstrating different mitigation strategies, such as colour scheme options for a building and to show how tree planting can mature over time to reduce effects.
3. Scale and format
The photomontages need to be presented at the correct scale and format. The Landscape Institute has published detailed guidelines on preparing photomontages in their presentation “Photography and photomontage in landscape and visual impact assessment” (Landscape Institute Advice Note 01/11).
Ideally the image should be printed at a size that, when one holds it up in front of one’s eyes at arm’s length it matches the view. This often means producing large images, especially if one widens the field of view to show the image in its full context – the equivalent to someone turning their head to look around.
Such large formats are suitable for public exhibition and public inquiries but since most planning applications are made online it is often more practical to have an A3 format with the “before and after” on the same page. The advantage of a PDF is that it can be enlarged on screen as long as the image is at sufficient resolution, however, this can be a problem if computer servers are constrained by file size.
4. Quantification
Finally, a picture cannot paint all the words! Although everyone can form their own opinion on the look of an image there must still be a rigorous quantification of the visual impact based on the established criteria of combining sensitivity and magnitude.
Magnitude can easily be judged from the image, but the factoring in sensitivity is not so easily understood by the public who often cannot understand the final level of significance that has been determined.
The final assessment of effects must be set out clearly in the text of the document and the correct degree of significance assigned.
The photomontage is a very useful tool that is here to stay, particularly as public consultation in decision making becomes more important. Nonetheless, it remains only a tool and the standard methodology for assessing impacts must be followed to give an unbiased assessment.
This article was written as a contribution to the EIA Quality Mark’s commitment to improving EIA practice.
Chris McDermott is a principal landscape architect at The Landmark Practice ([email protected])
