1.11.1.              Overview

  1. Zones of Theoretical Visibility (ZTVs) and visualisations (wirelines or wirelines and photomontages) are graphical images produced to assist and illustrate the SLVIA and the cumulative assessment. The methodology used for viewpoint photography and photomontages has been produced in accordance with the NatureScot guidance on Visual Representation of Wind Farms, Version 2.2 (2017), the Guidelines for Landscape and Visual Impact Assessment, Third Edition (GLVIA 3) (Landscape Institute and IEMA, 2013) and the Landscape Institute Technical Guidance Note on Visual Representation of Development Proposals (2019).
  2. ZTVs and visual representations are produced on the assumption that the Proposed Development wind turbines are modelled relative to Lowest Astronomical Tide (LAT) sea level at their maximum blade tip height (355 m). The sea level for LAT is modelled at -2.27 m below Ordnance datum (OD), which is equivalent of LAT for the closest tidal station in Aberdeen. The height of LAT within the Proposed Development array area relative to mean sea level (MSL) is between -2.46 and -2.87 m.

Zone of Theoretical Visibility (ZTV)

  1. The ZTVs in Figure 15.5 – 15.13 have been calculated using GIS software to generate a ZTV of the Proposed Development to demonstrate the theoretical extent of visibility from any point in the study area.
  2. The ZTVs are based on Ordnance Survey Terrain 5 digital terrain model (DTM) data, to produce detailed ZTV plots to assess particular effects, such as along the coastline. The computer model will include the entire study area and takes account of atmospheric refraction and the Earth's curvature. The resulting ZTV plots have been overlaid on Ordnance Survey mapping at an appropriate scale and presented as figures using desktop publishing or graphic design software.
  3. Cumulative ZTV plots based on the intervisibility of the Proposed Development and other relevant developments within the study area have also been produced.
  4. There are limitations which should be considered in the interpretation and use of the ZTV as follows.
  • Where the ZTV has been calculated using Ordnance Survey Terrain 5 DTM, this will not account for the screening effects of vegetation or built form unless added in the form of OS Vectormap data or digitally added and stated on the figure.
  • The ZTVs are based on theoretical visibility from 2 m above ground level.
  • The Blade Tip ZTV does not indicate the decrease in visibility that occurs with increased distance from the array area. The nature of what is visible from 3 km away will differ markedly from what is visible from 10 km away, although both are indicated on the Blade Tip ZTV as having the same level of visibility.
  • There is a wide range of variation within the visibility shown on the ZTV, for example, an area shown on the blade tip ZTV as having visibility of seven WTGs may gain views of the smallest extremity of blade tips, or of seven full WTGs. This can make a considerable difference in the effects of the Proposed Development on that area.
    1. These limitations mean that while the ZTV is used as a starting point in the assessment, providing an indication of where the Proposed Development will be theoretically visible and tending to present a worst-case or over-estimate the actual visibility. The information drawn from the ZTV is checked by field survey observation.
    2. The SLVIA includes a Horizontal Angle ZTV to show the horizontal field of view (in degrees) that may be affected by views of the WTGs.

1.11.2.              Baseline photography

Overview

  1. Once a view has been selected, the location is visited, confirmed, and assessed with the aid of a wireline or similar visualisation in the field. A photographic record is taken to record the view and the details of the viewpoint location and associated data are recorded to assist in the production of visualisations and to validate their accuracy. 
  2. The following photographic information is recorded:
  • date, time, weather conditions and visual range;
  • GPS recorded 12 figure grid reference accurate to ~5-10 m;
  • GPS recorded Above Ordnance Datum (AOD) height data;
  • use of a fixed 50 mm focal length lens is confirmed;
  • horizontal field of view (in degrees); and
  • bearing to Proposed Development.
    1. The photographs used to produce the photomontages were taken at the times of day and locations agreed with the consultees using Canon EOS 5D and 6D Digital SLR cameras, with a fixed lens and a full-frame (35 mm negative size) complementary metal oxide semiconductor (CMOS) sensor. The photographs were taken on a tripod with a pano-head at a height of approximately 1.5 m above ground.
    2. Whilst no two-dimensional image can fully represent the real viewing experience, the visualisation aims to provide a realistic representation of the offshore elements, based on current information and photomontage methodology.
  • Guidelines for LVIA (GLVIA3) para 8.22 state – ‘In preparing photomontages, weather conditions shown in the photographs should (with justification provided for the choice) be either:
  • representative of those generally prevailing in the area; or
  • taken in good visibility, seeking to represent a maximum visibility scenario when the development may be highly visible’.
    1. In preparing photomontages for the SLVIA, photographs have been taken in favourable weather conditions during periods of ‘very good’ or ‘excellent’ visibility conditions - seeking to represent a maximum visibility scenario when the Proposed Development may be most visible.

1.11.3.              Visualisations

  1. Photomontages have been produced in accordance with NatureScot Visual Representation of Windfarms Guidance (NatureScot, 2017) and Landscape Institute (2019) Technical Guidance Note (TGN) 06/19 Visual Representation of Development Proposals.
  2. A photomontage is a visualisation which superimposes an image of a Proposed Development upon a photograph or series of photographs. Photomontage is a widespread and popular visualisation technique, which allows changes in views and visual amenity to be illustrated and assessed, within known views of the ‘real’ landscape.
  3. To create the baseline panorama, the frames are individually cylindrically projected and then digitally joined to create a fully cylindrically projected panorama using Adobe Photoshop or PTGui software. This process avoids the wide-angle effect that will result should these frames be arranged in a perspective projection, whereby the image is not faceted to allow for the cylindrical nature of the full 360-degree view but appears essentially as a flat plane.
  4. Tonal alterations are made using Adobe software to create an even range of tones across the photographs once joined.
  5. The baseline photographs and cumulative wireline visualisations shown for each viewpoint cover a 90-degree field of view (or in some cases, up to 360-degree), which accords with NatureScot guidance. These are cylindrically projected images and should be viewed flat at a comfortable arm’s length.
  6. The photographs are also joined to create planar projection panoramas using PTGui software. These are used in the creation of the 53.5 degree field of view photomontages.
  7. Wireline representations that illustrate the Proposed Development and set within a computer-generated image of the landform are used in the assessment to predict theoretical appearance of the WTGs. These are produced with Resoft WindFarm software and are based on OS Terrain 5 DTM. There are limitations in the accuracy of digital terrain model (DTM) data so that landform may not be picked up precisely and may result in WTGs being more or less visible than is shown, however, the use of OS Terrain 5 minimises these limitations. Where descriptions within the assessment identify the numbers of WTGs visible this refers to the illustrations generated and therefore the reality may differ to a degree from these impressions.
  8. Daytime visualisations and wirelines show a WTG model which represents the maximum development scenario of the Proposed Development in the array area and allow the potential proportions of the WTGs to be appreciated from the visualisations.
  9. Fully rendered photomontages have been produced for the agreed viewpoints using Resoft WindFarm software, to provide a photorealistic image of the appearance of the Proposed Development. In the daytime photomontages modelled representations are combined with the baseline view photographs to create a photorealistic rendered photomontage image of the development.
  10. ‘Panoramic photomontages’ are produced in the SLVIA with a 53.5° HFoV, based on relevant guidance (NatureScot, 2017) and due to their suitability to encompass the horizontal spread of the Proposed Development and show the turbines at a representative scale and distance. In some views, two adjacent 53.5° photomontages will be required to capture the horizontal spread of the Proposed Development.
  11. The 53.5 degree field of view wirelines and photomontages are prepared using a planar projected image and should also be viewed flat at a comfortable arm’s length. These images are each printed on paper 841 x 297mm (half A1) which provides for a relatively large scale image.
  12. In the wirelines, the WTGs are shown with the central WTGs facing the viewer directly, with the full rotor diameter visible at its tallest extent. In the photomontages, the WTG rotors are shown with a random appearance with the central WTGs facing the viewer directly.
  13. Rendering of the WTGs in the photomontages is as photorealistic as possible to the conditions shown in each viewpoint photograph. There may be some variation in the appearance and visibility of the WTGs between the viewpoints, as they are rendered to suit the conditions shown in each of the different viewpoint photographs, which have some unavoidable degree of variation in terms of lighting and weather conditions. The key requirement is that the WTGs need to be rendered with sufficient contrast against the skyline backdrop to illustrate their maximum visibility scenario in each image. Photomontages have been prepared to depict how the Proposed Development will appear to illustrate the worst-case. The full suite of viewpoint photomontages should be viewed to gain an impression of the likely visual effects of the Proposed Development.

1.11.4.              Night-time visualisations

  1. The visual effect of the Proposed Development at night has been assessed in Chapter 15, informed by the night-time photomontage visualisations produced from representative viewpoints, to visually represent aviation and marine navigation lighting at night. Photomontages showing aviation lighting at 2,000 cd are provided to support the assessment.
  2. Night-time visualisations have been produced using a combination of using Resoft’s WindFarm software’s aviation module software for positioning of the lights, 3D modelling software that can simulate lighting conditions, referencing existing lighting imagery/atmospheric conditions from the baseline photographs and professional judgement using photoshop.
  3. The appearance of the lights in the night-time photomontages emulates how lights appear in the other parts of the baseline photographs. A light shown in a photograph tends to have a slight ‘halo’ (or bokeh) around it due to the way a camera lens renders out-of-focus points of light. This is not the way lights are seen in reality, as they tend to much more defined as point sources. However, the proposed lighting has been shown in this way for consistency with the lights in the baseline photographs.

1.11.5.              Information on limitations of visualisations

  1. The photographs and other graphic material such as wirelines and photomontages used in this assessment are for illustrative purposes only and, whilst useful tools in the assessment, are not considered to be completely representative of what has been apparent to the human eye. The assessments are carried out from observations in the field and therefore may include elements that are not visible in the photographs. Limitations of photomontages are set out further below.
  2. The photomontage visualisations of the Proposed Development (and any wind farm proposal) have a number of limitations when using them to form a judgement on visual impact. These include the following:

 

1.11.6.              Technical Methodology - Visualisations

  1. In accordance with the requirements of Landscape Institute (2019) Technical Guidance Note 06/19 Table 1.11   Open ▸ sets out the technical information for the preparation of the visualisations contained in Annex 10.6.
Table 1.11:
Technical Methodology - Visualisations

Table 1.11: Technical Methodology - Visualisations

 


1.12. References

Literature

Inch Cape Offshore Limited (2018) Environmental Impact Assessment Report.

Forth and Tay Offshore Wind Developers Group (FTOWDG) (2011) Regional Seascape Character Assessment: Aberdeen to Holy Island.

Kincardine Offshore Wind Farm (April 2019). Development Specification and Layout Plan.

Kincardine Offshore Wind Farm (April 2019). Lighting and Marking Plan.

Land Use Consultants (2011).  An assessment of the impacts of climate change on Scottish landscapes and their contribution to quality of life: Phase 1 - Final report.  Scottish Natural Heritage Commissioned Report No. 488

Landscape Institute and IEMA (2013). Guidelines for Landscape and Visual Impact Assessment: Third Edition (GLVIA3). Routledge.

Landscape Institute (2019). Visual Representation of Development Proposals.

Landscape Institute (2021). Assessing landscape value outside national designations, Technical Guidance Note (TGN) 02/21.

MMO (2018) Seascape Character Assessment for the South West Inshore and Offshore marine plan areas.

Natural England (2012). An Approach to Seascape Character Assessment.

Natural England (2014). An Approach to Landscape Character Assessment.

NatureScot (2015). Scotland’s Biodiversity – a Route Map to 2020.

NatureScot (2021). Assessing the Cumulative Impact on Onshore Wind Energy Developments.

NatureScot (2012). Guidance on Assessing the Impact of Coastal Landscape and Seascape.

NatureScot (2017). Siting and Designing Wind farms in the Landscape, Guidance (Version 3) (herein referred to as ‘NatureScot Siting and Designing’).

NatureScot (2017). Visual Representation of Wind farms, Guidance (Version 2.2)

NatureScot (2018). Guidance Note. Coastal Character Assessment.

NatureScot (2019) Scottish Landscape Character Types Map and Descriptions.

Neart na Gaoithe Offshore Wind Farm (March 2018). Environmental Impact Assessment Report.

Neart na Gaoithe Offshore Wind Farm (August 2020). Lighting and Marking Plan.

Neart na Gaoithe Offshore Wind Farm (June 2020) Development Specification and Layout Plan.

Northumberland Coast AONB (2020-2024). Northumberland Coast AONB Management Plan.

Scottish Government (July 2021) Inch Cape Offshore Wind Farm decision to vary s36 consent.

Seagreen Offshore Wind Farm (May 2020). Development Specification and Layout Plan.

Seagreen Offshore Wind Farm (May 2020). Lighting and Marking Plan.

Seagreen Wind Energy Limited (September 2018). Environmental Impact Assessment Report.

Seagreen Wind Energy Limited (January 2022). SeaGreen S36C Application, Screening Report.

The Planning Inspectorate (2019). Advice Note 17 Cumulative Effects Assessment.

The Planning Inspectorate (2018). Advice Note Nine: Rochdale Envelope.

Planning Policy

Aberdeenshire Council (2017). Aberdeenshire Local Development Plan.

Aberdeenshire Council (2017) Aberdeenshire Local Development Plan – Special Landscape Areas Supplementary Planning Guidance.

Angus Council (2016). Angus Local Development Plan 2016.

East Lothian Council (2018). East Lothian Local Development Plan.

East Lothian Council (2018). East Lothian Local Development Plan, Special Landscape Areas Supplementary Planning Guidance.

Fife Council (2017). Fife Local Development Plan.

Fife Council (2009) Fife Local Landscape Designation Review

Northumberland Coast AONB (2013) Northumberland Coast AONB Landscape Sensitivity and Capacity Study.

Northumberland County Council (2019). Northumberland Draft Local Plan.

Northumberland County Council (2010). Landscape Character Assessment.

Scottish Borders Council (2016). Scottish Borders Local Development Plan

Scottish Borders Council (2012). Local Landscape Designations Supplementary Planning Guidance.

Scottish Government (2014). National Planning Framework 3 (NPF3)

Scottish Government (2015). Scotland’s National Marine Plan: A Single Framework for Managing Our Seas

Scottish Government (2014). Scottish Planning Policy (SPP).

Scottish Government (2021). Scotland 2045 (Fourth National Planning Framework – Draft)

UK Department for Business, Energy and Industrial Strategy, White Consultants with Northumbria University (2020). Offshore Energy Strategic Environmental Assessment, Review and Update of Seascape and Visual Buffer Study for Offshore Wind Farms.

Legislation

Civil Aviation Authority (2016). The Air Navigation Order 2016

HM Government (1949). National Parks and Access to the Countryside Act 1949. Available at: https://www.legislation.gov.uk/ukpga/Geo6/12-13-14/97.

HM Government (2000). Countryside and Rights of Way Act 2000. Available at: https://www.legislation.gov.uk/ukpga/2000/37/contents.

HM Government (2009). Marine and Coastal Access Act 2009. Available at: https://www.legislation.gov.uk/ukpga/2009/23/contents.