Landscape Institute Guidelines: What Do GLVIA3 and LITGN-2024-01 Mean for Your Project?

At the heart of Landscape and Visual Impact Assessments (LVIA) are two core documents published by the Landscape Institute: Guidelines for Landscape and Visual Impact Assessment (GLVIA3) and Technical Guidance Note LITGN-2024-01. Together, these documents underpin best practice for all robust LVIA work undertaken in the UK.

Whether you are preparing a planning application for a housing development, infrastructure project, energy scheme, or commercial facility, your project’s credibility — and likelihood of approval — will often hinge on the quality and methodology of your LVIA work. In this context, adhering to the principles of GLVIA3 and LITGN-2024-01 is not optional; it is a professional imperative.

GLVIA3: a framework for professional judgement

First published in 2013 by the Landscape Institute and the Institute of Environmental Management and Assessment (IEMA), GLVIA3 sets out a structured framework for assessing the potential effects of a proposed development on landscape elements and visual receptors. It is not intended to be a mechanistic checklist or formula, but rather a flexible, reasoned process that allows for site-specific interpretation and the exercise of informed professional judgement.

Key stages of the GLVIA3 process include:

• Establishing a baseline, including the character, value, and sensitivity of the landscape and visual receptors.
• Describing the magnitude of change a proposal would introduce.
• Judging significance of effect, often through combining sensitivity and magnitude.
• Considering cumulative effects and mitigation.
• Reporting findings transparently and without advocacy.

GLVIA3 emphasises the need for impartiality and rigour. Assessors are required to explain their reasoning clearly, particularly when it comes to determining what is or isn't significant in planning terms. This principle applies to all LVIAs, whether within Environmental Impact Assessment (EIA) regulations or in standalone Landscape and Visual Appraisals (LVA).

LITGN 01/24: clarifying GLVIA3 in practice

In August 2024, the Landscape Institute published Technical Guidance Note LITGN 01/24: GLVIA3 – Notes and Clarifications, a significant update intended to support practitioners and improve consistency across the industry. It replaces earlier drafts and reflects the cumulative feedback of the GLVIA Panel, Landscape Institute members, and wider practice.

While it does not alter the core methodology of GLVIA3, this guidance refines how its principles should be interpreted and applied. It addresses areas where inconsistent approaches have developed, often due to ambiguity in the original text or evolving planning practice.

Key areas of clarification include:

• LVIA vs Landscape and Visual Appraisal (LVA): The Note confirms that the distinction is not about 'simpler' vs 'more detailed' reports, but rather whether or not the project falls under the EIA Regulations. If it does, an LVIA is required within the Environmental Statement. If not, a non-EIA LVA may suffice. However, both must be prepared with the same professional rigour.
• Use of terminology: The guidance warns against vague or formulaic labels such as "moderate adverse" or "low-medium significance" without explanation. Practitioners must define their terms, explain their judgement, and avoid disguising subjective opinion as fact.
• Value and susceptibility: LITGN 01/24 reaffirms that value and susceptibility are separate but interrelated. Their combination informs sensitivity, but this must be context-specific — not a generic assumption. For example, a low-value landscape might still have high susceptibility to certain types of development.
• Professional judgement and transparency: The Note clarifies that judgement must not be reduced to mathematical matrices. While structured methods may help, they must not replace narrative reasoning. Assessors should clearly explain how they reached a conclusion, particularly where a moderate effect is considered significant or not significant.
• Significance in planning terms: The guidance reiterates that the purpose of determining significance is to inform planning decisions, not to produce academically precise distinctions. What matters is whether a given effect is likely to influence the outcome of a planning application, which must be supported by transparent reasoning.

The role of Chartered Landscape Architects

A major implication of both GLVIA3 and the 2024 Clarifications is the elevated importance of professional competence. Assessors must not only be methodologically accurate but also capable of exercising transparent professional judgement. This is why the Landscape Institute recommends that LVIA work be undertaken by Chartered Members of the Landscape Institute (CMLI) — a benchmark that ensures a recognised level of expertise and accountability.