Adapting Actively on the Fly: Relevance-Guided Online Meta-Learning with Latent Concepts for Geospatial Discovery
Organizations: University of Michigan, Ann Arbor, MI, USA · Washington University in St. Louis, St. Louis, MO, USA
Abstract
In environmental monitoring, data collection is often costly, sparse, and shaped by urgent public-health needs. This is particularly true for cancer-causing PFAS (Per- and polyfluoroalkyl substances) contamination, where discussions with domain experts and environmental organizations highlight the need to strategically identify high-risk, under-observed regions under tight sampling budgets. More broadly, similar challenges arise in disaster response and public health settings, where dynamic environments make it essential to efficiently uncover hidden targets from limited ground truth. Yet sparse and biased geospatial labels limit the applicability of existing learning-based methods, such as reinforcement learning. To address this, we propose a unified geospatial discovery framework that integrates active learning, online meta-learning, and concept-guided reasoning. Our approach introduces two key innovations built on a shared notion of concept relevance, capturing how domain-specific factors influence target presence: a concept-weighted uncertainty sampling strategy, where uncertainty is modulated by learned relevance from readily available concepts such as land cover and source proximity; and a relevance-aware meta-batch formation strategy that promotes semantic diversity during online-meta updates, improving generalization in dynamic environments. We evaluate our framework on PFAS contamination discovery as a real-world inspired environmental monitoring task, demonstrating robust target discovery under limited data and changing conditions.
Figures & tables
| Baseline | Description |
|---|---|
| GA | G reedy A pproach: A non-adaptive, single-pass method that queries the highest-confidence regions after supervised training. |
| DIG | D omain- I nformed G reedy: A single-pass baseline that leverages domain-informed simulation to estimate contamination and rank regions without learning or sequential adaptation. |
| Prithvi | A standard supervised geospatial model that iteratively selects high-confidence samples with online updates during inference. ( Blumenfeld, 2023 ) . |
| UCB | OWL-GPS with a bandit-based exploration and exploitation sampling policy using U pper C onfidence B ounds ( Auer et al., 2002 ) . |
| AL | A ctive L earning: Exploration-focused, pure uncertainty based sampling during training and inference ( Cacciarelli and Kulahci, 2023 ) . |
| AML | A ctive M eta L earning: OWL-GPS with meta-batch updates driven by latent representations of previously queried samples ( Kaddour et al., 2020 ) . |
| Year | Method | Acc. | F-score | Prec. | Recall | SR |
| LC | GA | 46 0.8 | 35 1.0 | 48 0.9 | 40 1.3 | 47 1.4 |
| AL | 58 1.8 | 41 1.5 | 50 1.2 | 47 1.9 | 60 1.0 | |
| Prithvi | 61 1.2 | 40 1.4 | 51 1.5 | 56 1.7 | 61 1.8 | |
| UCB | 55 2.1 | 45 1.7 | 53 1.3 | 58 1.5 | 55 1.3 | |
| AML | 91 1.3 | 48 1.3 | 46 1.6 | 50 1.8 | 90 1.1 | |
| OML | 92 1.7 | 48 1.6 | 47 1.8 | 50 1.9 | 92 1.5 |
| Baseline | Key Limitations in OWL-GPS setting |
|---|---|
| UCB | Assumes independent arms; fails under spatial correlations, leading to inefficient exploration. |
| AL | Uncertainty-based sampling without relevance or feedback-driven correction; often selects informative samples yet fails to discover target-rich regions. |
| DIG | Domain-informed approach based on pollutant transport simulation; lacks adaptation to newly observed samples, limiting sequential performance. |
| GA | Exploits high-confidence regions early with no exploration; resulting in suboptimal performance. |
| Prithvi | Statically trained with online updates at inference, but not designed for strategic exploration. |
| AML | Relies on task identity and few-shot setup; fails in geospatial streams without task boundaries. |
| Variant | Accuracy | F-score | Precision | Recall | SR ( ) |
|---|---|---|---|---|---|
| No Relevance Encoder (No-RE) | 86 1.8 | 56 1.7 | 50 1.5 | 74 1.8 | 95 2.0 |
| Random Meta-Training Set | 67 2.0 | 56 2.1 | 57 1.6 | 46 1.7 | 69 1.4 |
| No Relevance-Guided Sampling (No-RG) | 72 1.9 | 55 1.7 | 55 2.0 | 50 1.7 | 77 1.5 |
| Ours (Full Framework) | 88 2.0 | 65 2.0 | 57 2.0 | 83 2.0 | 98 1.0 |
Appendix figures & tables11 assets
Supplementary material from the paper’s appendix.
Appendix
| SR Performance across varying with | ||
| 94% 1.0 | 98% 1.0 | 98% 1.9 |
| Search Budget ( ) | Accuracy (%) | F-score (%) | SR (%) |
|---|---|---|---|
| 10 | 80 1.5 | 50 1.1 | 43 1.3 |
| 30 | 81 1.3 | 56 1.2 | 58 1.6 |
| 50 | 88 2.0 | 65 2.0 | 98 1.0 |
| Buffer configuration | Accuracy (%) | F1-score (%) | SR (%) |
|---|---|---|---|
| Core Reservoir | 77 1.9 | 50 1.1 | 88 0.5 |
| Core = Reservoir | 87 2.2 | 56 1.0 | 98 1.1 |
| Core Reservoir (Ours) | 88 2.0 | 65 2.0 | 98 1.0 |
| Clustering approach | Accuracy (%) | F-score (%) | SR (%) ( ) |
|---|---|---|---|
| DBSCAN | 81 2.2 | 57 1.6 | 94 1.1 |
| Ours | 88 2.0 | 65 2.0 | 98 1.0 |
| Method | Accuracy (%) | F-score (%) | SR (%) |
|---|---|---|---|
| Ours (RG MLP) | 85 1.7 | 56 1.8 | 94 2.3 |
| Ours | 88 2.0 | 65 2.0 | 98 1.0 |
| Orthogonalization | Accuracy (%) | F-score (%) | SR (%) ( ) |
|---|---|---|---|
| No | 80 1.0 | 56 1.5 | 86 0.7 |
| Yes (our framework) | 88 2.0 | 65 2.0 | 98 1.0 |
Adaptive Sampling
Adaptive sampling allocates limited data, measurements, or computation where they are expected to be most useful.
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