Beyond the Townhall: Spatial Anchoring and LLM Agents for Scalable Participatory Urban Planning

TL;DR

This paper presents a scalable digital platform using spatial anchoring and LLM assistants within a digital twin to enhance participatory urban planning, improving recall and community engagement.

Contribution

It introduces an immersive, spatially anchored virtual walkthrough combined with LLM assistants to facilitate inclusive and effective public participation in sustainability projects.

Findings

Spatially anchored immersive presentation improved information recall.

Participants shifted focus from inconveniences to community benefits.

Participants provided more constructive, solution-focused feedback.

Abstract

Participatory urban planning is central to sustainable city-making, yet the technically demanding nature of such interventions often limits meaningful involvement by diverse publics. We introduce a scalable digital participation platform that embeds sustainability projects within a navigable digital twin. Citizens experience a guided virtual walkthrough with audio narration employing the method of loci and spatial anchoring to support mnemonic encoding and recall. This immersive interface is augmented by two purpose-built LLM assistants: one delivers source-grounded factual clarifications, while the other facilitates reflective discussion. We evaluated this system in a randomized controlled online experiment (N = 195) against conventional industry practices (static visualizations and text-based consultations). Results show that spatially anchored immersive presentation significantly improved information recall, which substantially shifted participants' attention from individual inconveniences to collective, community-oriented sustainability benefits. Consequently, participants provided significantly more constructive, solution-focused feedback to the (simulated) municipality. These findings establish a practical tool for cities and policymakers to foster inclusive, democratic participation in sustainability transitions.