Glossary

Note that the definition of this term varies in common parlance and also in ISO 5725 which invokes the need for both trueness and precision in order to achieve an accurate result.

Shorthand term for a clear film sheet (typically now made of polyester) which has a photograph of a view printed on it which can be held up to compare the image on the film directly with the same view in the field.

High-resolution imagery captured from airborne platforms including aircraft, drones, or satellites. Modern aerial photography for architectural visualisation combines precise camera calibration, georeferencing, and digital processing to create accurate visual contexts for proposed developments. Advanced photogrammetry techniques transform overlapping aerial images into detailed 3D site models that serve as the foundation for visualisations. Current architectural practice uses aerial photography for site analysis, context studies, and as base imagery for photomontages showing proposed developments from elevated viewpoints.

Measured in degrees, minutes and seconds, or degrees and decimal parts of a degree. The amount of turn between two lines rotated from a common point, e.g. the line of sight as one moves from looking in one direction to another (Cf. field of view), where a 360 degree turn on the spot would bring the viewer back ‘full circle’ to the original direction. The combination of an angle in a horizontal plane (azimuth), with an angle in a vertical plane (elevation) can define all possible directions of view from a point, hence forming the basis for devices such as LiDAR/laser scanners.

The size of the hole in a solid plane through which light is made to pass within a camera lens assembly. Typically adjustable, it could be likened to the pupil in an eye dilating in lower light levels. It is typically measured as f-numbers (focal ratio numbers) which represent the ratio of the system’s focal length to the diameter of the hole. Larger f numbers denote smaller apertures, letting less light through (and therefore requiring a longer exposure time) but are associated with a greater depth of field.

(as per the mathematical function)

A digital visualisation technology that overlays 3D models of proposed developments onto real-world environments, viewable through devices such as smartphones, tablets, or specialised AR headsets. Modern AR systems use precise geolocation, computer vision, and motion tracking to accurately position virtual architecture within physical spaces, allowing clients and planning authorities to experience proposed developments in context from multiple viewpoints. AR visualisations can include realistic materials, lighting, and even time-of-day simulations to accurately represent architectural proposals.

A visualisation that adheres to specific technical standards to ensure reliable representation of a proposed development’s appearance, scale, and visual impact. Modern AVR methodologies employ calibrated photography, precise GNSS positioning, verified 3D modelling, and systematic quality control processes. Current industry standards often classify AVRs by levels (0-4) depending on the degree of verifiable accuracy and detail required for different planning contexts.

A form of optical distortion which would have the effect of making a grid of lines (which could be taken as simplification of the components of an image) progressively more curved the further they are from the centre of the view. It is an inevitable product of the optics of all lenses but most noticeable when using wide-angle lenses or when shooting very close to the subject.

The regulatory or planning authority which is the recipient of visualisations and which will determine or be consulted upon the planning process.

The process of reducing the size of an image file. The process may involve some loss of metadata and/or image detail (such as number of colours).

The understanding of the wider view containing the proposed development site, encompassing all relevant landscape/ townscape/ seascape features in the view.

Co-ordinates are one way to pinpoint where and how far something is from a starting point (origin). Cartesian co-ordinates do this in each of three directions perpendicular to each other (typically represented as x, y and z axes, providing easting, northing and elevation). In situations where the curvature of the earth is a factor, a co-ordinate system needs to be defined. See co-ordinate reference system.

Most x,y,z co-ordinate systems for spatial location are achieved via a process known as projection. This creates a flat or ‘planar’ surface to represent a small section of the earth’s curved surface, albeit only by distortion. Because of the need to keep the difference between the true location on the planet’s surface and the equivalent position on its planar representation small, there have developed thousands of co-ordinate systems around the world. It is thus critically important to know which CRS lies behind the position quoted for spatial data. If a point has been identified in reference to the typical international default setting for many devices of WGS84, and mapped as if it were in reference to OSGB36 without transforming the data first, within Great Britain it will be out of place horizontally by between 0 and 70m. GIS software can perform the necessary transformation between CRSs but the most accurate are mathematically complex and slow down processing. See also OSGB36.

A sensor which is smaller than a Full Frame Sensor. There are many formats, including APS-C, DX, Foveon, Micro Four-thirds, APS-H, Sony RX-10, Sony RX-100, 4.6x.

Selecting part of an image for further use.

A visualisation technique for displaying panoramic views where the image is mapped onto a virtual cylinder surrounding the viewer. In architectural visualisation, cylindrical projections maintain vertical lines as straight while allowing horizontal fields of view up to 360 degrees, making them ideal for showing proposed developments within their wider context. Modern visualisation software automatically handles the mathematical transformations required to create these projections, ensuring accurate representation of architectural forms across the panorama.

This is a physical point, the locational parametres of which define it as a reference point for a co-ordinate system.

The range of distance within a photograph where elements appear in acceptable focus, a critical factor in architectural visualisation for controlling visual hierarchy and directing attention to key design elements. In professional architectural photography, depth of field is precisely controlled through aperture selection and focal length to either isolate specific architectural features or maintain clarity throughout a scene. Current visualisation techniques can simulate depth of field effects in rendered images to match the optical characteristics of the reference photography used in photomontages.

Catches or stops in a device used to mechanically control rotation.

Any proposal that results in a change to the landscape and/or visual environment.

A 3D model that represents the earth’s surface including all objects on it (buildings, vegetation, etc.), providing a complete visual context for architectural proposals. Current architectural visualisation uses high-resolution DSMs derived from drone surveys and LiDAR to create accurate context models, ensuring proposed developments are shown with correct relationships to existing structures and vegetation.

Digital Terrain Model. A 3D representation of the bare ground surface without vegetation or buildings, essential for accurate placement of architectural visualisations in the landscape. Modern DTMs utilise LiDAR and photogrammetry data with resolutions capable of capturing subtle topographic features that influence how architecture sits within its context.

A comprehensive, systematic process and document that evaluates the potential environmental effects of a proposed development before planning decisions are made. In architectural visualisation, EIA requires a range of accurately Verified Views and visualisations showing the development from sensitive receptors and key viewpoints. Modern EIA visualisation standards require specific methodology, including verified photography, accurate 3D modelling, and consistent presentation formats that clearly communicate visual impacts alongside other environmental considerations. EIA visualisations typically include before-and-after views, seasonal variations, and cumulative impact assessments when multiple developments are proposed in the same area.

Effective Focal Length. In this guidance this refers to the apparent focal length of final presented images. For example an image produced using a 50 mm lens may be carefully enlarged by 150% and printed to give the image that would have been achieved by using a 75mm lens – an EFL of 75mm.

An ellipsoid is the name given to a flattened sphere, modelled mathematically by rotating an ellipse about a main axis. Planet Earth’s true shape (or geoid) is approximated as an oblate ellipsoid (because the Equatorial diameter is larger than the polar diameter) although different ellipsoids have been used over time for this purpose. Currently WGS84 and GRS1980 represent two important standards for ellipsoids but are for most purposes the same. In the UK the geoid is higher than the ellipsoid by over 60 metres.

Exchangeable Image File Format. EXIF is a standard that defines the format for images, but tends to be used as shorthand for just the hidden image metadata embodied within each image file, such as author, aperture, shutter speed, tags.

The amount of light reaching the camera sensor (or film). This is affected by the amount of available ambient light (or artificial illumination), the aperture and shutter speed.

A colloquial way of describing a lens with a large maximum aperture (permitting faster shutter speeds).

A sensor which is 36mm x 24mm in size. See also cropped frame sensor.

The extent of the observable scene captured by a camera or experienced by a viewer, measured in degrees both horizontally and vertically. In architectural visualisation, matching the field of view between photographs, renderings, and human perception is essential for creating accurate representations of how proposed developments will appear in reality. Modern visualisation standards specify appropriate fields of view for different visualisation purposes, typically recommending 40-50 degrees horizontal field of view for standard architectural visualisations to match natural human perception.

The distance between the optical centre (nodal point) of the lens and the focal point, which corresponds with the film/sensor plane when the image is in focus. For example 28mm, 35mm, 50mm.

See aperture.

Digital images can be stored in different file formats, typically engineered to optimise the quality of the image and metadata retained with file size, but also sometimes because equipment may create or require proprietary formats. Examples are JPG and RAW (See JPG and RAW).

Single photographic shot composed to include elements of a view.

Geo-referenced data is spatial data (points, lines or areas) that is referenced to a location on the earth’s surface, typically using a defined x,y,z (Cartesian) co-ordinate system, such as OSGB36 (in the UK). The term geo-referencing often refers to the process of taking an image, identifying on it an array of points whose spatial position within an existing projection system is agreed as known (‘control points’) and then moving the image (‘rubbersheeting’) so that the whole image can be mapped into the system. GIS software is often used to assist this process.

GIMP is a free and open-source raster graphics editor used for image retouching and editing, free-form drawing, converting between different image formats, and more specialised tasks (N.B. Other editors are available).

Geographic Information System. Computer software which enables the user to undertake a range of processes on spatial data such as rendering, symbolising, visualising, georeferencing, transforming, analysing, and converting (to other formats).

Guidance for Landscape and Visual Impact Assessment published by the LI in conjunction with IEMA. The current edition (2013) is the 3rd, hence referred to as GLVIA3.

A network of satellites that provides precise positioning data used in architectural visualisation to accurately place digital models in real-world environments. Modern GNSS technology integrates multiple satellite constellations (including GPS, Galileo, GLONASS, and BeiDou) to achieve positioning accuracy within centimetres when used with enhancement techniques.

The original satellite positioning system developed by the United States, now commonly used in architectural visualisation to georeference photographs, models, and on-site assessments. Modern smartphones and specialised equipment use GPS data to ensure accurate placement of proposed architectural elements in visualisations.

A photography and rendering technique that captures or simulates a wider range of light intensities than standard imaging, essential for architectural visualisation to show both bright and shadowed areas with proper detail. Modern HDR techniques use multiple exposure blending, tone mapping, and computational photography to create images that better represent how the human eye would perceive a space or building. In architectural visualisation, HDR is crucial for accurate representation of both interior spaces with varying light conditions and exterior facades under different lighting scenarios.

Horizontal Field of View. The difference (typically measured in degrees and parts of a degree) between the lines defining the extent of view in the horizontal plane. See also VFoV.

A measurement of a digital camera sensor’s sensitivity to light. In architectural photography, lower ISO settings (100-400) are typically used for exterior shots in good lighting to maximise image quality, while higher settings may be necessary for interior spaces. Modern cameras offer significantly improved high-ISO performance, allowing quality architectural photography in challenging light conditions.

A compressed image format commonly used for sharing and presenting architectural visualisations. While convenient for web display and client presentations, JPG compression can reduce fine detail important in architectural elements. Modern architectural visualisation workflows typically use higher quality settings or alternative formats for critical approval stages.

Where the horizontal dimension is larger than the vertical (Cf. descriptions of paper layout).

A physical device that sits with the camera to ensure that it is perfectly level and necessary to obviate subsequent cropping of panoramas.

Light Detection And Ranging. A remote sensing technology that measures distances using laser light, creating highly accurate 3D scans of buildings and environments. Modern LiDAR is now integrated into certain smartphones and tablets, making basic 3D scanning more accessible for architectural visualisation. Professional LiDAR systems provide sub-millimeter accuracy for creating precise digital twins of existing buildings and sites, which serve as the foundation for accurate visualisations of proposed architectural interventions.

Knowing how close you really are to a location you identify.

Local Planning Authority

A structured methodology for evaluating how a proposed development will affect both the physical landscape and people’s views of it. LVIA visualisation requires accurate representations of the development in its landscape context, typically from a range of distances and viewpoints agreed with planning authorities. Contemporary LVIA practice uses calibrated photography, precise camera positioning, and sophisticated rendering techniques to create visualisations that demonstrate how architecture will appear within natural and rural landscapes. These visualisations must accurately represent scale, mass, materials, and seasonal variations, often requiring specialised techniques to show the development in both summer (full vegetation) and winter (minimal vegetation) conditions to ensure comprehensive impact assessment.

Landscape and Visual Appraisal (non-EIA) – essentially the same as LVIA, but not required to satisfy the formal requirements of EIA.

metres Above Ordnance Datum (a UK-wide basis for ‘sea-level’ or zero elevation).

The three-dimensional form and volume of a building or architectural element, representing its overall shape and scale without detailed features. In architectural visualisation, massing studies are often the first stage of visual communication, allowing stakeholders to understand the general form, proportion, and spatial relationship of proposed developments. Modern visualisation tools enable interactive massing models that can be viewed from multiple angles and contexts to assess their impact on surroundings.

A measurement of a digital camera’s resolution (one million pixels). For architectural visualisation, cameras with higher megapixel counts (typically 24MP+) provide the detail necessary for large-format prints and planning submissions where fine architectural elements must be clearly visible. However, lens quality and proper technique remain equally important for professional results.

Metadata is the term for descriptive data contained within the EXIF (Exchangeable Image File Format) data that is embedded within a digital image files such as JPG, TIFF & RAW. Includes details such as aperture, shutters speeds, lens specifications, plus time and date and may include geographical coordinates.

Crossover point of light within lens.

This is the co-ordinate reference system used by the Ordnance Survey for the OS British grid. It uses a 6 digit coordinate system for eastings and northings, together with metres Above Ordnance Datum (mAOD).

Additional information or imagery which is lain over an existing image. In real-world environments typically involves use of clear film (acetate) or translucent paper. In software may be achieved by adding a layer and adjusting its transparency.

A wide-format image or series of connected images that show an expanded view beyond what is captured in a standard photograph. In architectural visualisation, panoramas provide essential context by showing proposed developments within their broader surroundings, helping stakeholders understand spatial relationships and visual impact. Current panoramic techniques use specialised camera equipment, precision rotation control, and advanced stitching software to create geometrically accurate wide-view images that maintain proper proportions of architectural elements throughout the expanded field of view.

A panoramic (Pano) head is a piece of photographic equipment, mounted to a tripod, which allows photographers to shoot a sequence of images with precise overlaps around the entrance pupil of a lens to produce a panorama. The primary function of a Pano head is to precisely set the axis of rotation about the entrance pupil for a given lens or focal length, eliminating parallax error.

This is where foreground objects appear to move relative to background objects as the camera is rotated. A simple way to demonstrate parallax is to hold a single finger up in front of your eye and look at a view, then rotate your head from side to side. The position of the background, relative to the finger, will move. Within the context of panoramic photography parallax errors can be introduced if the camera is rotated around its mount to take a panorama, rather than the camera being rotated to keep the camera iris in the same position. This can result in serious geometry issues, particularly with foreground elements of the view. It can be resolved with the correct use of a Pano head.

Portable Document Format: a cross-platform digital file type widely used to display formatted text and graphics.

The visual phenomenon where objects appear smaller as their distance from the viewer increases and parallel lines converge toward vanishing points. In architectural visualisation, accurate perspective representation is fundamental to creating believable and dimensionally correct images of proposed developments. Current visualisation workflows use camera matching techniques to ensure that 3D models are rendered with exactly the same perspective characteristics as the reference photography, maintaining proper scale relationships between existing and proposed elements.

The smallest controllable element of a raster image, typically square in shape. It has no particular dimensions.

Pixels Per Inch. Measurements of pixel density (resolution) of an electronic image. The industry standard for high quality printed images is usually 300 pixels per inch. However, PPI for large format prints used for exhibitions and billboards may differ. PPI should not be confused with DPI (Dots Per Inch) which is a measure of printing density.

A visualisation technique that combines photographs of existing sites with rendered images of proposed architectural developments, created using specialised software to ensure accurate scale, perspective, and lighting integration. Modern photomontages use advanced rendering engines, precise camera matching, and materials simulation to create highly realistic representations that satisfy planning requirements.

A hybrid visualisation showing both the wireframe outline and rendered surfaces of a proposed development composited into a photograph of the existing site. This technique provides transparency about the exact position and scale of proposed architecture while also communicating materials and design intent. Current software allows for accurate shadow casting and lighting analysis in these visualisations.

A visualisation technique that maps an image onto a flat surface, replicating how a camera lens creates an image on a sensor. In architectural visualisation, planar projections are the standard for Verified Views and planning submissions as they maintain the same perspective relationships as the original photograph. Modern visualisation software correctly handles planar projections when integrating 3D architectural models with site photography, ensuring that vertical and horizontal lines are represented with the same perspective characteristics as in the original view.

The closeness of agreement between instances. For instance three darts thrown at a dartboard would have been thrown with precision if they all landed inside the bullseye, whether or not that was the intended target.

The perpendicular distance from a printed image at which the exact perspective ‘as seen by the camera’ is reconstructed.

Although the processes in each case are related, two different applications of projection are particularly relevant:

As a typical method of creating a flat map from the earth’s curved surface;

The transforming of an image created by a lens or other sensor into a more appropriate form for viewing (see cylindrical / planar projection).

An approach which is commensurate with the situation it is being applied to in terms of inputs of time, methodological sophistication, resources and costs.

An unprocessed image format that preserves all data captured by a camera’s sensor, providing maximum flexibility for post-processing architectural images. Professional architectural photographers typically shoot in RAW format to ensure optimal quality for visualisation work, allowing precise adjustments to exposure, white balance, and detail that are essential for accurate representation of designs.

Individuals and/or defined groups of people who have the potential to be affected by a proposal. (GLVIA3)

The process in which the direction of light is diverted as it passes through a transparent material such as the atmosphere, water or glass.

The process of generating realistic or stylised images from 3D architectural models using specialised software that simulates materials, lighting, and environmental conditions. Contemporary architectural rendering combines physically accurate light simulation, advanced material representation, and environmental effects to create visualisations that accurately predict how completed buildings will appear. Current rendering technologies allow architects to demonstrate seasonal variations, different times of day, and various weather conditions to provide comprehensive visual assessment of proposed developments.

The level of detail captured in digital imagery, typically measured in pixels for digital images or dots per inch (DPI) for printed materials. In architectural visualisation, high resolution is essential for showing fine details of materials, textures, and architectural features. Modern visualisation standards for planning submissions typically specify minimum resolution requirements (often 300 DPI for printed materials) to ensure that stakeholders can properly assess design details and that distant elements remain clearly visible in context views.

A precision enhancement technology for satellite positioning that improves standard GNSS/GPS accuracy from metres to centimetres. In architectural visualisation, RTK allows extremely precise positioning of cameras and reference points when creating Verified Views for planning submissions. Modern RTK systems use cellular networks or local base stations to provide correction data in real-time, ensuring that visualisations accurately represent the position and scale of proposed developments in relation to their surroundings.

The relative size or extent of built form

A term applied to specific receptors, combining judgments of the susceptibility of the receptor to the specific type of change or development proposed and the value related to that receptor. (GLVIA3)

The light-sensitive component in digital cameras that captures images for architectural photography and visualisation. Modern professional cameras use full-frame or medium format sensors that provide exceptional dynamic range, colour accuracy, and detail essential for architectural work. The size and quality of a sensor significantly affects how architectural elements are rendered in terms of detail, colour, and the ability to capture both highlights and shadows in challenging lighting conditions typical of architectural subjects.

The length of time that a camera’s sensor (traditionally the photographic film) is exposed to light.

Scottish Natural Heritage

Technical Guidance Note (as produced by the LI)

Technical Information Note (as produced by the LI)

The Highland Council

Instead of being mounted directly above the centre of the tripod the camera fixing point is mounted on an adjustable side bar to instead enable the iris of the camera to be located above the tripod centre.

An attachment plate used to attach a camera to a tripod, to achieve a level plane for photography.

An assessment methodology similar to LVIA but focused specifically on urban environments, evaluating how proposed architecture will affect the character and visual qualities of built-up areas. TVIA visualisation focuses on how new developments integrate with existing urban fabric, addressing relationships with historic buildings, street scenes, and public spaces. Modern TVIA visualisation techniques include accurate street-level views, verified photomontages from key urban viewpoints, and sometimes sequential views along important routes to demonstrate how the development would be experienced by pedestrians moving through the urban environment. TVIA visualisations must accurately represent materials, detailing, and how the development’s mass and scale relate to surrounding buildings, often requiring high-resolution rendering of complex urban contexts.

A photomontage created following a rigorous, documented process to ensure accurate representation of scale, position, and appearance of proposed developments. Modern verified photomontages use precise camera positioning data, calibrated photography, accurate 3D modelling, and documented quality control procedures to create visualisations that can be relied upon for planning decisions. Current best practice includes providing technical methodology statements with verified photomontages, explaining the equipment, software, and verification processes used to ensure accuracy.

Subjected to a quality assurance process to confirm that what is being presented is an accurate reflection of the true situation.

Vertical Field of View. The difference (typically measured in degrees and parts of a degree) between the lines defining the extent of view in the vertical plane. See also HFoV.

These can be actual or virtual. They are points in space from where the view is obtained.

The process of creating visual media that communicates architectural proposals, including static images, animations, interactive models, VR experiences, and augmented reality applications. Contemporary architectural visualisation integrates multiple technologies including photorealistic rendering, real-time engines, parametric modelling, and environmental simulation to accurately represent how buildings will appear and perform in their context. Visualisations serve both technical planning requirements and marketing purposes, helping stakeholders understand spatial, material, and experiential qualities of proposed architecture.

Generic term for material produced to demonstrate existing, hypothetical or proposed views to others.

The adjustment of colour temperature in photography to render whites and other colours accurately regardless of lighting conditions. In architectural visualisation, consistent white balance between site photography and rendered elements is crucial for creating seamless photomontages. Professional architectural photographers use calibrated colour targets and post-processing techniques to ensure neutral colour representation, particularly important when visualizing materials with subtle colour variations such as concrete, stone, and metal finishes.

A three-dimensional representation showing the edges and structural framework of an architectural model without surfaces or materials. Modern architectural visualisation often begins with wireframe models created in BIM software, which are then developed into more detailed renderings. Wireframes provide transparent representations of proposed developments that clearly communicate massing and form.

A simplified outline representation of a proposed development superimposed on a photograph of the existing site, created by extracting the visible edges from a 3D architectural model precisely positioned in the view. Current visualisation software enables accurate matching of the camera position, focal length, and perspective to ensure the wireline correctly represents how the development would appear from specific viewpoints.

Zone of Theoretical Visibility: A computer-generated map showing areas from which a proposed development might be visible, accounting for topography and, in advanced analyses, existing buildings and vegetation. Modern ZTV mapping uses high-resolution digital terrain models, LiDAR data, and GIS software to provide sophisticated visibility analysis essential for planning applications. Current ZTV methodologies can include seasonal vegetation changes, distance-based visual impact assessment, and cumulative impact analysis when multiple developments are proposed.

The incorporation of Building Information Modelling data into architectural visualisations, ensuring that visual representations accurately reflect the technical specifications, materials, and spatial arrangements defined in the building’s digital twin. Modern visualisation workflows directly link BIM models with rendering software to create consistent, accurate visualisations that update automatically when the underlying design changes. This integration ensures consistency between technical documentation and visual representation, reducing errors and improving the accuracy of planning submissions.

The use of unmanned aerial vehicles (drones) to capture photographs and video footage of sites and buildings from previously inaccessible vantage points. In architectural visualisation, drone imagery provides crucial context for proposed developments, allowing visualisation of projects from multiple elevations and distances. Modern drone technology incorporates precision GPS positioning, automated flight paths, and high-resolution cameras to create accurate visual records that can be integrated with 3D models for photomontages, site analysis, and contextual studies.