---
license: other
license_name: research-use-cite-source
license_link: https://github.com/ChangeCapsInRS/MOSAIC-SEN2-CC
task_categories:
  - image-text-to-text
tags:
  - earth-observation
  - change-detection
  - sentinel-2
  - remote-sensing
language:
  - en
size_categories:
  - 10K<n<100K
---

# danvinci/mosaic_sen2_cc_change_detection

Multi-image change-detection reformat of the
[MOSAIC-SEN2-CC dataset](https://github.com/ChangeCapsInRS/MOSAIC-SEN2-CC)
(Tuzlupinar et al., IEEE JSTARS 2025), prepared for vision-language
fine-tuning of `LiquidAI/LFM2.5-VL-1.6B`.

## Splits

| split        | rows         | source                         |
|--------------|--------------|--------------------------------|
| `train`      | 29281 | full MOSAIC TRAIN partition    |
| `validation` |   700   | balanced 33% positive sample   |

## Schema

Each row is a (before_img, after_img, prompt, answer, schema_id) tuple:

| field        | type        | description                                  |
|--------------|-------------|----------------------------------------------|
| `before_img` | PIL Image   | Sentinel-2 RGB tile before the change window |
| `after_img`  | PIL Image   | Sentinel-2 RGB tile after the change window  |
| `prompt`     | string      | Per-schema predicate prompt                  |
| `answer`     | string      | JSON-shaped object **or** literal `"null"`   |
| `schema_id`  | string      | One of 7 change-event schemas (see below)    |

## Change-event schemas (7)

Each schema lives at `schemas/<schema_id>.json` and defines the positive-event
field spec. Predicate prompts in the dataset reference these contracts.

- `ConstructionProgress` — building / road footprint expansion
- `FloodExtentChange` — water surface expansion (excludes stable water)
- `IceExtentChange` — sea / lake / glacier ice retreat or growth
- `ThermalHotspot` — wildfire / volcanic / industrial heat anomaly
- `UrbanChangeDelta` — generic urban land-cover delta
- `VegetationStress` — drought / disease / clear-cut signal
- `WetlandChange` — wetland surface delta

## Usage

```python
from datasets import load_dataset
ds = load_dataset("danvinci/mosaic_sen2_cc_change_detection")
print(ds)
# DatasetDict({
#     train: Dataset(...29281 rows),
#     validation: Dataset(...700 rows),
# })

row = ds["train"][0]
row["before_img"]  # PIL.Image (RGB Sentinel-2 tile)
row["after_img"]   # PIL.Image
row["prompt"]      # "Did urban-change-delta occur..."
row["answer"]      # JSON object or "null"
row["schema_id"]   # "UrbanChangeDelta"
```

## Auxiliary files at repo root

- `schemas/<schema_id>.json` — 7 field-spec contracts
- `mosaic_reformat_v0.jsonl` — original row-metadata (before/after tile paths,
  split assignment, expected_output) used to build the prepared Arrow

## Provenance + license notes

This is a **derivative reformat** of the
[MOSAIC-SEN2-CC dataset](https://github.com/ChangeCapsInRS/MOSAIC-SEN2-CC),
not the canonical release. The reformat collapses MOSAIC's change-detection
annotations into a uniform image-text-to-text supervised contract suitable
for VLM fine-tuning, but the underlying tile pairs and labels originate from
the upstream MOSAIC project.

License posture (the upstream repo does **not** ship an explicit LICENSE
file — typical academic-dataset gray zone):

- **Sentinel-2 imagery** is redistributable: ESA Copernicus Sentinel data is
  released under the Copernicus "free, full and open access" license.
- **MOSAIC change-detection annotations**: research/academic use under
  citation is the established norm; non-research / commercial redistribution
  may require explicit permission from the original authors. Contact the
  upstream maintainers via the GitHub repo for any non-research use.
- **The reformat itself** (this repo's prompt structure, schema definitions,
  Arrow layout) is shared under the same research-use-cite-source posture
  as the upstream MOSAIC.

Built during the DPhi Space x Liquid AI hackathon (May 2026) as part of the
[liquid_space](https://github.com/danvinci/liquid_space) project.

## Citation

Always cite the upstream MOSAIC-SEN2-CC paper when using this reformat:

```bibtex
@ARTICLE{karaca2025robust,
  author={Busra Tuzlupinar and Enes Ozelbas and Mehmet Fatih Amasyali and Ali Can Karaca},
  journal={IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing},
  title={Introducing MOSAIC-SEN2-CC: A Multispectral Dataset and Adaptation Framework for Remote Sensing Change Captioning},
  year={2025},
  volume={18},
  pages={25410-25426},
  doi={10.1109/JSTARS.2025.3615113}
}
```