--- license: cc-by-sa-4.0 pretty_name: TerraMesh size_categories: - 1M **A planetary‑scale, multimodal analysis‑ready dataset for Earth‑Observation foundation models.** **TerraMesh** merges data from **Sentinel‑1 SAR, Sentinel‑2 optical, Copernicus DEM, NDVI and land‑cover** sources into more than **9 million co‑registered patches** ready for large‑scale representation learning. **Dataset to be released soon.** ![Examples from TerraMesh](assets%2Fexamples.png) Samples from the TerraMesh dataset with seven spatiotemporal aligned modalities. Sentinel-2 L2A uses IRRG pseudo-coloring and Sentinel-1 RTC is visualized in db scale as VH-VV-VV/VH. Copernicus DEM is scaled based on the image value range with an additional 10 meter buffer to highlight flat scenes. --- ## Dataset organisation The archive ships two top‑level splits `train/` and `val/`, each holding one folder per modality. `terramesh.py` includes code for data loading, see [Usage](#Usage). ```text TerraMesh ├── train │   ├── DEM │   ├── LULC │   ├── NDVI │   ├── S1GRD │   ├── S1RTC │   ├── S2L1C │   ├── S2L2A │   └── S2RGB ├── val │   ├── DEM │   └── ... └── terramesh.py ``` Each folder includes up to 889 shard files, containing up to 10240 samples each. Samples from MajorTom-Core are stored in shards with the pattern `majortom_{split}_{id}.tar` while shards with SSL4EO-S12 samples start with `ssl4eos12_`. Samples are stored as Zarr Zip files which can be loaded with `zarr` (Version <= 2.18) or `xarray.load_zarr()`. Each sample location includes seven modalities that share the same shard and sample name. Note that each sample only inludes one Sentinel-1 version (S1GRD or S1RTC) because of different processing versions in the source datasets. Each Zarr file includes aligned metadata as demonstrated by this S1GRD example from sample `ssl4eos12_val_0080385.zarr.zip`: ``` Size: 283kB Dimensions: (band: 2, time: 1, y: 264, x: 264) Coordinates: * band (band) = 0.16. ### Download You can download the dataset with the Hugging Face CLI tool. Please note that the dataset requires 16TB or storage. ```shell huggingface-cli download ibm-esa-geospatial/TerraMesh --repo-type dataset --local-dir data/TerraMesh ``` If you like to download only a subset of the data, you can specify it with `--include`. ``` # Only download val data huggingface-cli download ibm-esa-geospatial/TerraMesh --repo-type dataset --include "val/*" --local-dir data/TerraMesh # Only download a single modality (e.g., S2L2A) huggingface-cli download ibm-esa-geospatial/TerraMesh --repo-type dataset --include "*/S2L2A/*" --local-dir data/TerraMesh ``` ### Data loader We provide the data loading code in `terramesh.py` which is downloaded together with the dataset. For development use streaming, you can download the file via this [link](https://huggingface.co/datasets/ibm-esa-geospatial/TerraMesh/resolve/main/terramesh.py) or with: ``` wget https://huggingface.co/datasets/ibm-esa-geospatial/TerraMesh/resolve/main/terramesh.py ``` You can use the `build_terramesh_dataset` function to initalize a dataset, which uses the WebDataset package to load samples from the shard files. You can stream the data from Hugging Face using the urls or download the full dataset and pass a local path (e.g, `data/TerraMesh/`). ```python from terramesh import build_terramesh_dataset from torch.utils.data import DataLoader # If you only pass one modality, the modality is loaded with the "image" key dataset = build_terramesh_dataset( path="https://huggingface.co/datasets/ibm-esa-geospatial/TerraMesh/resolve/main/", # Streaming or local path modalities=["S2L2A"], split="val", batch_size=8 ) # Batch keys: ["__key__", "__url__", "image"] # If you pass multiple modalities, the modalities are returned using the modality names as keys dataset = build_terramesh_dataset( path="https://huggingface.co/datasets/ibm-esa-geospatial/TerraMesh/resolve/main/", # Streaming or local path modalities=["S2L2A", "S2L1C", "S2RGB", "S1GRD", "S1RTC", "DEM", "NDVI", "LULC"], split="val", batch_size=8 ) # Set batch size to None because batching is handled by WebDataset. dataloader = DataLoader(dataset, batch_size=None, num_workers=4) # Iterate over the dataloader for batch in dataloader: print("Batch keys:", list(batch.keys())) # Batch keys: ["__key__", "__url__", "S2L2A", "S2L1C", "S2RGB", "S1RTC", "DEM", "NDVI", "LULC"] # Because S1RTC and S1GRD are not present for all samples, each batch only includes one S1 version. print("Data shape:", batch["S2L2A"].shape) # Data shape: torch.Size([8, 12, 264, 264] # Dimensions [batch, channel, h, w]. The code removes the time dim from the source data. break ``` ### Data transform We provide some additional code for wrapping `albumentations` transform functions. We recommend albumentations because parameters are shared between all image modalities (e.g., same random crop). However, it requires some wrapping to bring the data into the expected shape. ```python import albumentations as A from albumentations.pytorch import ToTensorV2 from terramesh import build_terramesh_dataset, Transpose, MultimodalTransforms # Define all image modalities modalities = ["S2L2A", "S2L1C", "S2RGB", "S1GRD", "S1RTC", "DEM", "NDVI", "LULC"] # Define multimodal transform function that converts the data into the expected shape from albumentations val_transform = MultimodalTransforms( transforms=A.Compose([ # We use albumentations because of the shared transform between image modalities Transpose([1, 2, 0]), # Convert data to channel last (expected shape from albumentations) A.CenterCrop(224, 224), # Use center crop in val split # A.RandomCrop(224, 224), # Use random crop in train split # A.D4(), # Optionally, use random flipping and rotation for the train split ToTensorV2(), # Convert to tensor and back to channel first ], is_check_shapes=False, # Not needed because of aligned data in TerraMesh additional_targets={m: "image" for m in modalities} ), non_image_modalities=["__key__", "__url__"], # Additional non-image keys ) dataset = build_terramesh_dataset( path="https://huggingface.co/datasets/ibm-esa-geospatial/TerraMesh/resolve/main/", modalities=modalities, split="val", transform=val_transform, batch_size=8, ) ``` If you only use a single modality, you don't need to specify `additional_targets`. ### Returning metadata You can pass `return_metadata=True` to `build_terramesh_dataset()` to load center longitude and latitude, timestamps, and the S2 cloud mask as additional metadata. The resulting batch keys include: `["__key__", "__url__", "S2L2A", "S1RTC", ..., "center_lon", "center_lat", "cloud_mask", "time_S2L2A", "time_S1RTC", ...]`. Therefore, you need to update the `transform` if you use one: ```python ... additional_targets={m: "image" for m in modalities + ["cloud_mask"]} ), non_image_modalities=["__key__", "__url__", "center_lon", "center_lat"] + ["time_" + m for m in modalities] ``` For a single modality dataset, "time" does not have a suffix and the following changes for the `transform` are required: ```python ... additional_targets={"cloud_mask": "image"} ), non_image_modalities=["__key__", "__url__", "center_lon", "center_lat", "time"] ``` Note that center points are not updated when random crop is used. The cloud mask provides the classes land (0), water (1), snow (2), thin cloud (3), thick cloud (4), and cloud shadow (5), and no data (6). DEM does not return a time value while LULC uses the S2 timestamp because of the augmentation usign the S2 cloud and ice mask. Time values are returned as integer values but can be converted back to datetime with ```python batch["time_S2L2A"].numpy().astype("datetime64[ns]") ``` If you have any issues with data loading, please create a discussion in the community tab and tag `@blumenstiel`. --- ## Citation If you use TerraMesh, please cite: ```bibtex @article{blumenstiel2025terramesh, title={Terramesh: A planetary mosaic of multimodal earth observation data}, author={Blumenstiel, Benedikt and Fraccaro, Paolo and Marsocci, Valerio and Jakubik, Johannes and Maurogiovanni, Stefano and Czerkawski, Mikolaj and Sedona, Rocco and Cavallaro, Gabriele and Brunschwiler, Thomas and Bernabe-Moreno, Juan and others}, journal={Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR) Workshops}, year={2025} } ``` --- ## License TerraMesh is released under the **Creative Commons Attribution‑ShareAlike 4.0 (CC‑BY‑SA‑4.0)** license. --- ## Acknowledgements TerraMesh is part of the **FAST‑EO** project funded by the European Space Agency Φ‑Lab (contract #4000143501/23/I‑DT). The satellite data (S2L1C, S2L2A, S1GRD, S1RTC) is sourced from the [SSL4EO‑S12 v1.1](https://huggingface.co/datasets/embed2scale/SSL4EO-S12-v1.1) (CC-BY-4.0) and [MajorTOM‑Core](https://huggingface.co/Major-TOM) (CC-BY-SA-4.0) datasets. The LULC data is provided by [ESRI, Impact Observatory, and Microsoft](https://planetarycomputer.microsoft.com/dataset/io-lulc-annual-v02) (CC-BY-4.0). The cloud masks used for augmentating the LULC maps and provided as metadata are produced using the [SEnSeIv2](https://github.com/aliFrancis/SEnSeIv2/tree/main?tab=readme-ov-file) model. The DEM data is produced using [Copernicus WorldDEM-30](https://dataspace.copernicus.eu/explore-data/data-collections/copernicus-contributing-missions/collections-description/COP-DEM) © DLR e.V. 2010-2014 and © Airbus Defence and Space GmbH 2014-2018 provided under COPERNICUS by the European Union and ESA; all rights reserved