LVIA or TVIA: choosing the right visual assessment

The choice between a Landscape and Visual Impact Assessment and a Townscape and Visual Impact Assessment turns on what is being affected, not on how big the scheme is. An LVIA deals with effects on landscape character and on views in a rural or semi-rural setting. A TVIA does the same job where the receiving environment is built up, so the character being assessed is townscape: streets, blocks, plot patterns, roofscape and the quality of streets and spaces. Both share the same visual half. Both follow the method in the third edition of the Guidelines for Landscape and Visual Impact Assessment.

Landscape effects and visual effects are two separate judgements

GLVIA3 keeps two assessments running in parallel, and mixing them is the commonest fault in a weak report.

Landscape effects are effects on the landscape as a resource in its own right: its character, its elements, the pattern of hedgerows and field sizes, the tranquillity, the relationship between settlement and countryside. A building can harm landscape character even if almost nobody sees it, because the resource itself has changed.

Visual effects are effects on people and on the views they experience. The receptors are residents, walkers on a right of way, drivers, users of a viewpoint. A change can be highly visible and still cause only a small landscape effect, and the reverse happens too.

Report them under separate headings, with separate tables, and only bring them together in the summary of effects. A case officer reading a report that fuses the two cannot tell which conclusion rests on which evidence.

Where townscape replaces landscape as the receptor

Townscape is the built equivalent of landscape character. A TVIA describes the grain of the area, the prevailing plot widths, building heights and roof forms, the boundary treatments, the materials palette, the relationship of buildings to the street and the quality of the spaces between them, and then judges how the proposal changes those attributes.

The test for choosing is what the proposal actually touches. A farm building on the edge of a village affects field pattern, hedgerow structure and settlement edge, so it is an LVIA question. A five-storey block on a high street affects the street's rhythm and roofline, so it is a TVIA question. A site on the urban fringe can need both, and where a scheme sits within the setting of a designated heritage asset, the townscape work feeds the heritage assessment rather than replacing it.

Where a National Landscape or National Park is involved, the LVIA route is almost always the right one, and the statutory context changes. Section 85 of the Countryside and Rights of Way Act 2000 places a duty on relevant authorities in relation to National Landscapes, and the Levelling-up and Regeneration Act 2023 strengthened that duty so that authorities must seek to further the statutory purposes rather than simply have regard to them. Check the current wording before you rely on it, because the date those provisions took effect is worth checking at the point you write.

Sensitivity, magnitude and the reasoned significance judgement

GLVIA3 does not give you a matrix and tell you to fill it in. It asks for a reasoned, transparent professional judgement, built from two components.

Sensitivity combines susceptibility to the particular change proposed with the value attached to the receptor. A hedgerow-lined lane is susceptible to a large steel-clad building and much less susceptible to a buried cable. Value comes from designation, from published landscape character assessments, from recreational use and from local evidence, and the Landscape Institute's guidance on assessing value outside national designations is the reference to cite when a site has no designation.

Magnitude combines the size or scale of the change, its geographical extent, its duration and its reversibility. A construction compound present for 18 months is a temporary, reversible effect of large magnitude. A permanent building is smaller in area and much larger in duration.

Write the judgement out. Two sentences explaining why a moderate adverse effect is moderate and not major will survive scrutiny at appeal. A colour-coded table on its own will not.

Agreeing viewpoints before you take the photographs

Viewpoint selection is the part of the process most likely to be attacked, and the fix is procedural. Send the case officer and, where relevant, the National Landscape team a zone of theoretical visibility plot and a proposed schedule of viewpoints early, ideally at pre-application stage.

A defensible schedule covers representative views from settlements, views from public rights of way and open access land, views from recognised viewpoints and any promoted trail, views from the nearest heritage assets where setting is in play, and at least one close view that shows the proposal at its worst. Leaving out the worst view is the single fastest way to lose the officer's confidence.

Record the date, time, weather, camera, focal length, height above ground and grid reference for every photograph. Winter views matter for deciduous screening, so a summer-only survey of a site screened by hedgerows will be challenged, and rightly.

Visualisation types and what a verified view has to prove

The Landscape Institute's technical guidance on visual representation sets out a graded series of visualisation types, from an annotated baseline photograph up to a fully verified photomontage. The level you need rises with the sensitivity of the receptor and the contentiousness of the scheme.

A wireline shows the proposal's outline against the existing view and is enough for distant, low-sensitivity viewpoints. A photomontage renders the proposal into the photograph and is what most officers want for close and mid-range views. A verified view adds surveyed control points, so the camera position, the focal length and the model registration can be checked by a third party, and that is what a planning inspector will expect on a contested scheme in a designated landscape.

Do not mix types without saying so. Label each image with its type, the viewpoint number, the distance, the horizontal field of view and the correct viewing distance for a printed sheet. An unlabelled montage is evidence of nothing.

Illustrative example

An illustrative case: a farm diversification scheme proposing a 900 m² agricultural building converted to workshops with a new access track, 1.2 km outside a National Landscape boundary and visible from a ridge-top footpath. The zone of theoretical visibility is wide but the actual visibility is limited by a mature hedgerow that is thin in winter. The assessment reports a moderate adverse landscape effect at construction reducing to minor adverse at year 15, and a moderate adverse visual effect from the footpath that does not reduce, because the building sits above the hedge line. Naming that second effect honestly is what makes the rest of the report credible.

Mitigation and residual effects at year 15

Mitigation is assessed in sequence: avoid, reduce, remediate, then compensate. Say which of those each measure is. Repositioning a building to sit below a ridge is avoidance. A native hedgerow along the new access is reduction, and it does nothing in year one.

Residual effects are the effects that remain after mitigation, and landscape work conventionally reports them at completion and again at around year 15, when new planting has reached functional maturity. Be honest about what planting can achieve. A three-metre hedge will not screen a nine-metre building, and claiming otherwise invites a condition requiring a scheme that cannot be delivered.

Tree constraints on the site shape both the mitigation and the layout, so the arboricultural survey and the landscape work should be done together rather than in sequence. Categorising trees under BS 5837 categories A to U before the layout is fixed usually saves a redesign.

Choosing the right assessment for your site

Start with the receiving environment, not the scheme. If the character being changed is field pattern, settlement edge or open countryside, commission a landscape and visual assessment. If it is street grain, roofline and street quality, commission a townscape one. If the site straddles both, scope the question with the officer and agree in writing which document you are producing, because producing the wrong one wastes a survey season.

Both are labelled professional recommended rather than legally required, and councils expect a suitably qualified author working to GLVIA3. Where sunlight and overshadowing effects on neighbours also arise, those are separate technical tests handled by sun on ground and transient overshadowing methods rather than by the visual assessment.

For specialist technical reports, qualified professional input may be required. This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it.

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