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Supplementary Material and Datasheet for the WorldStrat Dataset

Neural Information Processing Systems

Does this timeframe match the creation timeframe of the data associated with the instances (e.g., recent crawl of old news articles)? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LCCS comprises of 23 classes and 14 sub-classes. The dataset, along with its machine-readable metadata, is hosted on CERN-backed Zenodo data repository: https://zenodo.org/record/6810792 Its long-term maintenance is discussed in the Datasheet. This includes reproducible code for the Benchmarks of Section 4 of [Cornebise et al., 2022a], following the ML Reproducibility Checklist [Pineau et al., 2021a,b]. The project also has its own website available at https://worldstrat.github.io/, The authors hereby state that they bear all responsibility in case of violation of rights, etc., and confirm that the data license is as follows: The low-resolution imagery, labels, metadata, and pretrained models are released under Creative Commons with Attribution 4.0 International (CC BY 4.0) The mean of the cloud coverage over the Sentinel 2 product areas is 7.98 %, with a standard deviation of 14.22. The quantiles are: 0.025: 0.00% 0.25: 0.00% 0.5: 0.66% 0.75: 10.05% 0.975: 49.95% It is important to note that this cloud cover percentage, as mentioned in the article and datasheet, is calculated on the entire product size of the provider, which varies in size but is much larger than the 2.5km we target. This means that even an image with a large cloud cover percentage can be cloud free, and in extreme cases (though unlikely), vice-versa. Also there are indeed considerable difference across sampled regions and land cover types. A simple example would be rainforests and non-desert equatorial regions. Using a strict no-cloud policy would make sampling enough low-resolution images either impossible or would make the temporal difference extremely large (up to 7 years for some AOIs). With that in mind, we strived to keep the cloud coverage as low as possible, ideally under 5%, while maintaining the temporal difference as small as possible.


SITS-DECO: A Generative Decoder Is All You Need For Multitask Satellite Image Time Series Modelling

Barrett, Samuel J., Sow, Docko

arXiv.org Artificial Intelligence

Earth Observation (EO) Foundation Modelling (FM) holds great promise for simplifying and improving the use of EO data for diverse real-world tasks. However, most existing models require additional adaptation before they can be used and are structured rigidly around particular data sources or training approaches. To address this, we take inspiration from large language models, where diverse tasks, both pre-training and downstream, are implicitly captured through next-token prediction over unified token sequences, leveraging the structure and diversity of the training data. We introduce SITS-DECO (Satellite Image Time Series-DECoder Only), a proof-of-concept generative model that applies this unified-sequence framing to EO data. Using a simple GPT-style decoder-only architecture, and demonstrate its ability to perform useful EO tasks (pixel-wise, multi-temporal, multi-modal crop-type classification) in a purely generative framework. Through symbolic prompting, we show that the model can perform multiple supervised and self-supervised tasks within a single unified architecture, without task- or modality-specific adaptation. Despite its simplicity and lack of spatial context, SITS-DECO outperforms much larger EO foundation models on crop-type classification (PASTIS-R) demonstrating that dense temporal sequence modelling is a critical missing ingredient in the current paradigm. This work exemplifies a data-centric modelling paradigm in which capability arises from the diversity and structure of the training data rather than from architectural complexity. SITS-DECO provides a lightweight, practical route to multi-modal, multi-task EO modelling, and a conceptual bridge toward future generative EO foundation models.


Chlorophyll-a Mapping and Prediction in the Mar Menor Lagoon Using C2RCC-Processed Sentinel 2 Imagery

Martínez-Ibarra, Antonio, González-Vidal, Aurora, Cánovas-Rodríguez, Adrián, Skarmeta, Antonio F.

arXiv.org Artificial Intelligence

The Mar Menor, Europe's largest coastal lagoon, located in Spain, has undergone severe eutrophication crises. Monitoring chlorophyll-a (Chl-a) is essential to anticipate harmful algal blooms and guide mitigation. Traditional in situ measurements are spatially and temporally limited. Satellite-based approaches provide a more comprehensive view, enabling scalable, long-term, and transferable monitoring. This study aims to overcome limitations of chlorophyll monitoring, often restricted to surface estimates or limited temporal coverage, by developing a reliable methodology to predict and map Chl-a across the water column of the Mar Menor. The work integrates Sentinel 2 imagery with buoy-based ground truth to create models capable of high-resolution, depth-specific monitoring, enhancing early-warning capabilities for eutrophication. Nearly a decade of Sentinel 2 images was atmospherically corrected using C2RCC processors. Buoy data were aggregated by depth (0-1 m, 1-2 m, 2-3 m, 3-4 m). Multiple ML and DL algorithms-including RF, XGBoost, CatBoost, Multilater Perceptron Networks, and ensembles-were trained and validated using cross-validation. Systematic band-combination experiments and spatial aggregation strategies were tested to optimize prediction. Results show depth-dependent performance. At the surface, C2X-Complex with XGBoost and ensemble models achieved R2 = 0.89; at 1-2 m, CatBoost and ensemble models reached R2 = 0.87; at 2-3 m, TOA reflectances with KNN performed best (R2 = 0.81); while at 3-4 m, RF achieved R2 = 0.66. Generated maps successfully reproduced known eutrophication events (e.g., 2016 crisis, 2025 surge), confirming robustness. The study delivers an end-to-end, validated methodology for depth-specific Chl-amapping. Its integration of multispectral band combinations, buoy calibration, and ML/DL modeling offers a transferable framework for other turbid coastal systems.



Towards Efficient Benchmarking of Foundation Models in Remote Sensing: A Capabilities Encoding Approach

Adorni, Pierre, Pham, Minh-Tan, May, Stéphane, Lefèvre, Sébastien

arXiv.org Artificial Intelligence

F oundation models constitute a significant advancement in computer vision: after a single, albeit costly, training phase, they can address a wide array of tasks. In the field of Earth observation, over 75 remote sensing vision foundation models have been developed in the past four years. However, none has consistently outperformed the others across all available downstream tasks. T o facilitate their comparison, we propose a cost-effective method for predicting a model's performance on multiple downstream tasks without the need for fine-tuning on each one. This method is based on what we call "capabilities encoding. " The utility of this novel approach is twofold: we demonstrate its potential to simplify the selection of a foundation model for a given new task, and we employ it to offer a fresh perspective on the existing literature, suggesting avenues for future research.


Leveraging Multi-Temporal Sentinel 1 and 2 Satellite Data for Leaf Area Index Estimation With Deep Learning

Wang, Clement, Debouchage, Antoine, Goldité, Valentin, Wery, Aurélien, Salzinger, Jules

arXiv.org Artificial Intelligence

The Leaf Area Index (LAI) is a critical parameter to understand ecosystem health and vegetation dynamics. In this paper, we propose a novel method for pixel-wise LAI prediction by leveraging the complementary information from Sentinel 1 radar data and Sentinel 2 multi-spectral data at multiple timestamps. Our approach uses a deep neural network based on multiple U-nets tailored specifically to this task. To handle the complexity of the different input modalities, it is comprised of several modules that are pre-trained separately to represent all input data in a common latent space. Then, we fine-tune them end-to-end with a common decoder that also takes into account seasonality, which we find to play an important role. Our method achieved 0.06 RMSE and 0.93 R2 score on publicly available data. We make our contributions available at https://github.com/valentingol/LeafNothingBehind for future works to further improve on our current progress.


These exclusive satellite images show that Saudi Arabia's sci-fi megacity is well underway

MIT Technology Review

Analysis of the satellite images by Soar Earth, an Australian startup that aggregates satellite imagery and crowdsourced maps into an online digital atlas, suggests that the workers have already excavated around 26 million cubic meters of earth and rock--78 times the volume of the world's tallest building, the Burj Khalifa. Official drone footage of The Line's construction site, released in October, indeed showed fleets of bulldozers, trucks, and diggers excavating its foundations. Visit The Line's location on Google Maps and Google Earth, however, and you will see little more than bare rock and sand. The strange gap in imagery raises questions about who gets to access high-res satellite technology. And if the largest urban construction site on the planet doesn't appear on Google Maps, what else can't we see? The Line is as controversial as it is futuristic.


Stochastic Functional Analysis and Multilevel Vector Field Anomaly Detection

Castrillon-Candas, Julio E, Kon, Mark

arXiv.org Artificial Intelligence

Massive vector field datasets are common in multi-spectral optical and radar sensors, among many other emerging areas of application. In this paper we develop a novel stochastic functional (data) analysis approach for detecting anomalies based on the covariance structure of nominal stochastic behavior across a domain. An optimal vector field Karhunen-Loeve expansion is applied to such random field data. A series of multilevel orthogonal functional subspaces is constructed from the geometry of the domain, adapted from the KL expansion. Detection is achieved by examining the projection of the random field on the multilevel basis. In addition, reliable hypothesis tests are formed that do not require prior assumptions on probability distributions of the data. The method is applied to the important problem of deforestation and degradation in the Amazon forest. This is a complex non-monotonic process, as forests can degrade and recover. Using multi-spectral satellite data from Sentinel-2, the multilevel filter is constructed and anomalies are treated as deviations from the initial state of the forest. Forest anomalies are quantified with robust hypothesis tests. Our approach shows the advantage of using multiple bands of data in a vectorized complex, leading to better anomaly detection beyond the capabilities of scalar-based methods.


Open High-Resolution Satellite Imagery: The WorldStrat Dataset -- With Application to Super-Resolution

Cornebise, Julien, Oršolić, Ivan, Kalaitzis, Freddie

arXiv.org Artificial Intelligence

Analyzing the planet at scale with satellite imagery and machine learning is a dream that has been constantly hindered by the cost of difficult-to-access highly-representative high-resolution imagery. To remediate this, we introduce here the WorldStrat dataset. The largest and most varied such publicly available dataset, at Airbus SPOT 6/7 satellites' high resolution of up to 1.5 m/pixel, empowered by European Space Agency's Phi-Lab as part of the ESA-funded QueryPlanet project, we curate nearly 10,000 sqkm of unique locations to ensure stratified representation of all types of land-use across the world: from agriculture to ice caps, from forests to multiple urbanization densities. We also enrich those with locations typically under-represented in ML datasets: sites of humanitarian interest, illegal mining sites, and settlements of persons at risk. We temporally-match each high-resolution image with multiple low-resolution images from the freely accessible lower-resolution Sentinel-2 satellites at 10 m/pixel. We accompany this dataset with an open-source Python package to: rebuild or extend the WorldStrat dataset, train and infer baseline algorithms, and learn with abundant tutorials, all compatible with the popular EO-learn toolbox. We hereby hope to foster broad-spectrum applications of ML to satellite imagery, and possibly develop from free public low-resolution Sentinel2 imagery the same power of analysis allowed by costly private high-resolution imagery. We illustrate this specific point by training and releasing several highly compute-efficient baselines on the task of Multi-Frame Super-Resolution. High-resolution Airbus imagery is CC BY-NC, while the labels and Sentinel2 imagery are CC BY, and the source code and pre-trained models under BSD. The dataset is available at https://zenodo.org/record/6810792 and the software package at https://github.com/worldstrat/worldstrat .


EarthNet2021: A large-scale dataset and challenge for Earth surface forecasting as a guided video prediction task

Requena-Mesa, Christian, Benson, Vitus, Reichstein, Markus, Runge, Jakob, Denzler, Joachim

arXiv.org Artificial Intelligence

Satellite images are snapshots of the Earth surface. We propose to forecast them. We frame Earth surface forecasting as the task of predicting satellite imagery conditioned on future weather. EarthNet2021 is a large dataset suitable for training deep neural networks on the task. It contains Sentinel 2 satellite imagery at 20m resolution, matching topography and mesoscale (1.28km) meteorological variables packaged into 32000 samples. Additionally we frame EarthNet2021 as a challenge allowing for model intercomparison. Resulting forecasts will greatly improve (>x50) over the spatial resolution found in numerical models. This allows localized impacts from extreme weather to be predicted, thus supporting downstream applications such as crop yield prediction, forest health assessments or biodiversity monitoring. Find data, code, and how to participate at www.earthnet.tech