Update README.md

README.md

@@ -13,7 +13,7 @@ viewer: false
 
 **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 release – End of June.**
+**Dataset to be released soon.**
 
 ![Examples from TerraMesh](assets%2Fexamples.png)
 
@@ -23,7 +23,7 @@ Samples from the TerraMesh dataset with seven spatiotemporal aligned modalities.
 
 ## Dataset organisation
 
-The archive ships two top‑level splits `train/` and `val/`, each holding one folder per modality. More details follow with the dataset release end of June.
+The archive ships two top‑level splits `train/` and `val/`, each holding one folder per modality. More details follow with the dataset release.
 
 ---
 
@@ -49,6 +49,53 @@ More details in our [paper](https://arxiv.org/abs/2504.11172).
 
 ---
 
+## Usage
+
+We provide the data loading code in `terramesh.py` which can be downloaded 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 or download the full dataset and pass a local path.
+```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", "S1GRD", "S1RTC", "DEM"], 
+    split='val',
+    batch_size=8
+)
+
+# Set batch size to None because batching is handled by WebDataset. Otherwise, set it to None in the dataset build 
+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', 'S1RTC', 'DEM']
+    
+    # The code removes the time dim from the source data
+    print("Data shape:", batch["S2L2A"].shape)
+    # Data shape: torch.Size([8, 12, 264, 264]
+    break
+```
+
+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: