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ssl4eo_eu_forest / dataset.py
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updated and improved version of the dataset loader
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import os
import json
import datasets
import rasterio
from datetime import datetime
from tqdm import tqdm
class SSL4EOEUForest(datasets.GeneratorBasedBuilder):
"""
SSL4EO-EU Forest Dataset Loader
This loader supports both directory-based scanning and prebuilt index streaming via JSONL.
It yields one sample at a time, making it compatible with Hugging Face's streaming mode.
Each sample includes:
- A list of image paths (one per timestamp)
- A single mask path
- Start and end timestamps for each image
- Sentinel tile IDs
- Bounding box metadata
Bounding boxes are stored as a dictionary of arrays:
{
"minx": [...], "maxx": [...], "miny": [...], "maxy": [...]
}
This avoids redundancy and simplifies downstream parsing.
"""
def _info(self):
return datasets.DatasetInfo(
description="SSL4EO-EU Forest dataset with grouped timestamps and bounding box metadata.",
features=datasets.Features({
"image_paths": datasets.Sequence(datasets.Value("string")),
"mask_path": datasets.Value("string"),
"start_timestamps": datasets.Sequence(datasets.Value("timestamp[ms]")),
"end_timestamps": datasets.Sequence(datasets.Value("timestamp[ms]")),
"sentinel_tile_ids": datasets.Sequence(datasets.Value("string")),
"bboxes": datasets.Features({
"minx": datasets.Sequence(datasets.Value("float32")),
"maxx": datasets.Sequence(datasets.Value("float32")),
"miny": datasets.Sequence(datasets.Value("float32")),
"maxy": datasets.Sequence(datasets.Value("float32")),
})
}),
citation="""@misc{ssl4eo_eu_forest,
author = {Nassim Ait Ali Braham and Conrad M Albrecht},
title = {SSL4EO-EU Forest Dataset},
year = {2025},
howpublished = {https://huggingface.co/datasets/dm4eo/ssl4eo-eu-forest},
note = {Funded by the EvoLand project under EU Horizon Europe grant No. 101082130.}
}""",
homepage="https://www.evo-land.eu",
license="CC-BY-4.0",
)
def _split_generators(self, dl_manager):
use_index = os.environ.get("HF_DATASET_USE_INDEX", "false").lower() == "true"
use_local = os.environ.get("HF_DATASET_LOCAL", "false").lower() == "true"
root = os.path.abspath(".") if use_local else dl_manager.download_and_extract(".")
if use_index:
index_path = os.path.join(root, "index.jsonl")
return [datasets.SplitGenerator(name="all", gen_kwargs={"index_path": index_path})]
else:
images_dir = os.path.join(root, "images")
masks_dir = os.path.join(root, "masks")
return [datasets.SplitGenerator(name="all", gen_kwargs={
"images_dir": images_dir,
"masks_dir": masks_dir
})]
def _generate_examples(self, index_path=None, images_dir=None, masks_dir=None):
if index_path:
with open(index_path, "r") as f:
for key, line in enumerate(f):
entry = json.loads(line)
entry["start_timestamps"] = [datetime.fromisoformat(ts) for ts in entry["start_timestamps"]]
entry["end_timestamps"] = [datetime.fromisoformat(ts) for ts in entry["end_timestamps"]]
yield key, entry
else:
sample_ids = sorted(os.listdir(images_dir))
key = 0
for sample_id in sample_ids:
sample = self._parse_sample(sample_id, images_dir, masks_dir)
if sample:
yield key, sample
key += 1
@staticmethod
def _parse_sample(sample_id, images_dir, masks_dir):
"""
Parses a single sample directory and returns a dictionary with all metadata.
Returns None if the sample is incomplete or malformed.
"""
sample_path = os.path.join(images_dir, sample_id)
if not os.path.isdir(sample_path):
return None
mask_path = os.path.join(masks_dir, sample_id, "mask.tif")
if not os.path.exists(mask_path):
return None
image_paths, start_ts, end_ts, tile_ids = [], [], [], []
minx_list, maxx_list, miny_list, maxy_list = [], [], [], []
for ts in sorted(os.listdir(sample_path)):
parts = ts.split("_")
if len(parts) != 3:
continue
try:
start = datetime.strptime(parts[0], "%Y%m%dT%H%M%S")
end = datetime.strptime(parts[1], "%Y%m%dT%H%M%S")
except ValueError:
continue
tile_id = parts[2]
image_path = os.path.join(sample_path, ts, "all_bands.tif")
if not os.path.exists(image_path):
continue
try:
with rasterio.open(image_path) as src:
bounds = src.bounds
except Exception:
continue
image_paths.append(image_path)
start_ts.append(start)
end_ts.append(end)
tile_ids.append(tile_id)
minx_list.append(bounds.left)
maxx_list.append(bounds.right)
miny_list.append(bounds.bottom)
maxy_list.append(bounds.top)
if not image_paths:
return None
return {
"image_paths": image_paths,
"mask_path": mask_path,
"start_timestamps": start_ts,
"end_timestamps": end_ts,
"sentinel_tile_ids": tile_ids,
"bboxes": {
"minx": minx_list,
"maxx": maxx_list,
"miny": miny_list,
"maxy": maxy_list
}
}
@classmethod
def generate_index(cls, dataset_dir, output_path="index.jsonl"):
"""
Scans the dataset directory and writes a streaming-friendly index.jsonl file.
Each line is a complete sample in JSON format.
"""
images_dir = os.path.join(dataset_dir, "images")
masks_dir = os.path.join(dataset_dir, "masks")
sample_ids = sorted(os.listdir(images_dir))
with open(output_path, "w") as f:
for sample_id in tqdm(sample_ids, desc="Generating index", unit="sample"):
sample = cls._parse_sample(sample_id, images_dir, masks_dir)
if sample:
sample["start_timestamps"] = [ts.isoformat() for ts in sample["start_timestamps"]]
sample["end_timestamps"] = [ts.isoformat() for ts in sample["end_timestamps"]]
sample["sample_id"] = sample_id
f.write(json.dumps(sample) + "\n")
print(f"✅ Index written to {output_path}")