Spatial-RAG: Spatial Retrieval Augmented Generation for Real-World Geospatial Reasoning Questions
Dazhou Yu, Riyang Bao, Ruiyu Ning, Jinghong Peng, Gengchen Mai, Liang Zhao
TL;DR
Spatial-RAG extends retrieval-augmented generation to real-world geospatial question answering by unifying structured spatial databases with LLM reasoning. It introduces a sparse-dense hybrid retriever and a multi-objective, Pareto-frontier approach to balance spatial constraints and semantic intent, with LLM-driven dynamic trade-offs for final generation. Empirical results across TourismQA and MapQA datasets show significant gains over strong baselines, demonstrating improved accuracy, precision, and ranking while highlighting the importance of each architectural component through ablations. The framework offers a practical path toward integrating geospatial grounding into natural language QA for applications in routing, recommendations, and urban planning.
Abstract
Answering real-world geospatial questions--such as finding restaurants along a travel route or amenities near a landmark--requires reasoning over both geographic relationships and semantic user intent. However, existing large language models (LLMs) lack spatial computing capabilities and access to up-to-date, ubiquitous real-world geospatial data, while traditional geospatial systems fall short in interpreting natural language. To bridge this gap, we introduce Spatial-RAG, a Retrieval-Augmented Generation (RAG) framework designed for geospatial question answering. Spatial-RAG integrates structured spatial databases with LLMs via a hybrid spatial retriever that combines sparse spatial filtering and dense semantic matching. It formulates the answering process as a multi-objective optimization over spatial and semantic relevance, identifying Pareto-optimal candidates and dynamically selecting the best response based on user intent. Experiments across multiple tourism and map-based QA datasets show that Spatial-RAG significantly improves accuracy, precision, and ranking performance over strong baselines.
