Land cover & change — ESA WorldCover v200 (2021)¶
ESA WorldCover 2021 (10 m, 11 classes) — a one-image land-cover map; the default reducer is mosaic because the collection is tiled rather than time-stepped.
Setup¶
The notebook reads the GEE service-account credentials from GEE_SERVICE_ACCOUNT / GEE_SERVICE_KEY environment variables. Both must be set before running this cell.
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import os
from pathlib import Path
import matplotlib.pyplot as plt
import numpy as np
from pyramids.dataset import Dataset as PyramidsDataset
from earthlens.gee import GEE, Catalog
OUT_DIR = Path('out') / 'land-cover-change'
OUT_DIR.mkdir(parents=True, exist_ok=True)
SERVICE_ACCOUNT = os.environ['GEE_SERVICE_ACCOUNT']
SERVICE_KEY = os.environ['GEE_SERVICE_KEY']
print(f'output directory: {OUT_DIR.resolve()}')
import os
from pathlib import Path
import matplotlib.pyplot as plt
import numpy as np
from pyramids.dataset import Dataset as PyramidsDataset
from earthlens.gee import GEE, Catalog
OUT_DIR = Path('out') / 'land-cover-change'
OUT_DIR.mkdir(parents=True, exist_ok=True)
SERVICE_ACCOUNT = os.environ['GEE_SERVICE_ACCOUNT']
SERVICE_KEY = os.environ['GEE_SERVICE_KEY']
print(f'output directory: {OUT_DIR.resolve()}')
2026-05-18 00:16:55 | INFO | pyramids.base.config | Logging is configured.
output directory: C:\gdrive\algorithms\remote-sensing\earthlens\docs\examples\gee\out\land-cover-change
Inspect the catalog entry¶
Before downloading anything, look at what the bundled catalog knows about the asset — bands, cadence, license, provider.
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cat = Catalog()
ds = cat.get_dataset('ESA/WorldCover/v200')
print(f'title: {ds.title}')
print(f'ee_type: {ds.ee_type}')
print(f'spatial_resolution: {ds.spatial_resolution} m')
print(f'extent.start_date: {ds.extent.start_date}')
print(f'extent.end_date: {ds.extent.end_date}')
print(f'default_reducer: {ds.default_reducer}')
print(f'license: {ds.license}')
print(f'provider: {ds.provider}')
print(f'#bands: {len(ds.bands)}')
print(f'band ids (first 5): {list(ds.bands)[:5]}')
cat = Catalog()
ds = cat.get_dataset('ESA/WorldCover/v200')
print(f'title: {ds.title}')
print(f'ee_type: {ds.ee_type}')
print(f'spatial_resolution: {ds.spatial_resolution} m')
print(f'extent.start_date: {ds.extent.start_date}')
print(f'extent.end_date: {ds.extent.end_date}')
print(f'default_reducer: {ds.default_reducer}')
print(f'license: {ds.license}')
print(f'provider: {ds.provider}')
print(f'#bands: {len(ds.bands)}')
print(f'band ids (first 5): {list(ds.bands)[:5]}')
title: ESA WorldCover 10m v200 (2021) ee_type: image_collection spatial_resolution: 10.0 m extent.start_date: 2021-01-01 extent.end_date: 2022-01-01 default_reducer: mosaic license: CC-BY-4.0 provider: esa #bands: 1 band ids (first 5): ['Map']
Download¶
Tiny AOI ([29.9, 30.1] lat, [31.1, 31.3] lon) at 30.0 m, raw cadence — keeps the synchronous download under EE's 32768-px per-axis cap.
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try:
gee = GEE(
start='2021-01-01',
end='2021-12-31',
variables={'ESA/WorldCover/v200': ['Map']},
lat_lim=[29.9, 30.1],
lon_lim=[31.1, 31.3],
temporal_resolution='raw',
path=str(OUT_DIR),
service_account=SERVICE_ACCOUNT,
service_key=SERVICE_KEY,
scale=30.0,
reducer='mosaic',
)
paths = gee.download(progress_bar=False)
print(f'wrote {len(paths)} GeoTIFF(s):')
for p in paths:
print(f' {p} ({p.stat().st_size / 1024:.1f} KB)')
download_ok = True
except Exception as exc:
if False:
print(f'live EE call failed (tolerated for this category): {type(exc).__name__}: {exc}')
paths = []
download_ok = False
else:
raise
try:
gee = GEE(
start='2021-01-01',
end='2021-12-31',
variables={'ESA/WorldCover/v200': ['Map']},
lat_lim=[29.9, 30.1],
lon_lim=[31.1, 31.3],
temporal_resolution='raw',
path=str(OUT_DIR),
service_account=SERVICE_ACCOUNT,
service_key=SERVICE_KEY,
scale=30.0,
reducer='mosaic',
)
paths = gee.download(progress_bar=False)
print(f'wrote {len(paths)} GeoTIFF(s):')
for p in paths:
print(f' {p} ({p.stat().st_size / 1024:.1f} KB)')
download_ok = True
except Exception as exc:
if False:
print(f'live EE call failed (tolerated for this category): {type(exc).__name__}: {exc}')
paths = []
download_ok = False
else:
raise
2026-05-18 00:17:04.577 | INFO | earthlens.gee.backend:_download_one_url_tile:757 - Wrote C:\gdrive\algorithms\remote-sensing\earthlens\docs\examples\gee\out\land-cover-change\ESA_WorldCover_v200_Map_20210101.tif (48685 bytes)
wrote 1 GeoTIFF(s): C:\gdrive\algorithms\remote-sensing\earthlens\docs\examples\gee\out\land-cover-change\ESA_WorldCover_v200_Map_20210101.tif (53.3 KB)
Quick preview¶
Load the first written GeoTIFF through pyramids and render the single band. (pyramids.dataset.Dataset is the project's GeoTIFF/NetCDF wrapper.)
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if not download_ok or not paths:
print('Skipping preview — no GeoTIFF was written.')
else:
pds = PyramidsDataset.read_file(str(paths[0]))
arr = pds.read_array()
if arr.ndim == 3:
arr = arr[0]
# Mask the dataset's nodata so the colormap doesn't get pinned to it.
nodata = pds.no_data_value
if nodata is not None:
try:
arr = np.ma.masked_equal(arr, float(nodata[0] if isinstance(nodata, (list, tuple)) else nodata))
except (TypeError, ValueError):
pass
fig, ax = plt.subplots(figsize=(6, 5))
im = ax.imshow(arr, cmap='viridis')
ax.set_title(f'{'ESA/WorldCover/v200'} / {'Map'}')
ax.set_xlabel('x (px)')
ax.set_ylabel('y (px)')
fig.colorbar(im, ax=ax, shrink=0.8)
plt.tight_layout()
plt.show()
print(f'value range: [{float(np.nanmin(arr)):.4g}, {float(np.nanmax(arr)):.4g}]')
if not download_ok or not paths:
print('Skipping preview — no GeoTIFF was written.')
else:
pds = PyramidsDataset.read_file(str(paths[0]))
arr = pds.read_array()
if arr.ndim == 3:
arr = arr[0]
# Mask the dataset's nodata so the colormap doesn't get pinned to it.
nodata = pds.no_data_value
if nodata is not None:
try:
arr = np.ma.masked_equal(arr, float(nodata[0] if isinstance(nodata, (list, tuple)) else nodata))
except (TypeError, ValueError):
pass
fig, ax = plt.subplots(figsize=(6, 5))
im = ax.imshow(arr, cmap='viridis')
ax.set_title(f'{'ESA/WorldCover/v200'} / {'Map'}')
ax.set_xlabel('x (px)')
ax.set_ylabel('y (px)')
fig.colorbar(im, ax=ax, shrink=0.8)
plt.tight_layout()
plt.show()
print(f'value range: [{float(np.nanmin(arr)):.4g}, {float(np.nanmax(arr)):.4g}]')
value range: [10, 90]
Tracking submitted jobs (asynchronous export)¶
The download above uses export_via="url" — a synchronous getDownloadURL round-trip. Nothing was queued, so there's no Earth Engine job to track.
To track an export instead, switch to an asynchronous sink (drive / gcs / asset) and pass wait_for_export=False so .download() returns a TaskInfo at submission time rather than blocking until completion. The cells below submit the same (asset_id, band, AOI, scale) request as an export_via="asset" task into the service account's own asset folder, then walk the four jobs-API calls (list_recent_tasks → wait_for_task_id → ee.data.getAsset → ee.data.deleteAsset) to make the job finish and tidy up. See track-batch-exports.ipynb for a deeper worked example.
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import ee
from earthlens.gee import list_recent_tasks, wait_for_task_id, cancel_task
# The asset goes into a `Folder` asset that we own. `GEE._export_via_batch`
# writes the actual image at `<asset_id>/<prefix>`, so `asset_id` here is
# the parent FOLDER (not the final image path). Both must be cleaned up.
_proj = ee.data._get_projects_path().removeprefix('projects/')
DEMO_FOLDER = f'projects/{_proj}/assets/earthlens-demo-land-cover-change'
print(f'demo folder: {DEMO_FOLDER}')
# Best-effort cleanup of leftover children from a previous run (so the
# folder is empty before we try to delete it below).
try:
for child in ee.data.listAssets({'parent': DEMO_FOLDER}).get('assets', []):
ee.data.deleteAsset(child['name'])
print(f'cleared leftover child: {child["name"]}')
ee.data.deleteAsset(DEMO_FOLDER)
print(f'cleared leftover folder: {DEMO_FOLDER}')
except Exception:
pass
# Create the parent folder — EE requires it to exist before a child write.
ee.data.createAsset({'type': 'Folder'}, DEMO_FOLDER)
print(f'created folder: {DEMO_FOLDER}')
import ee
from earthlens.gee import list_recent_tasks, wait_for_task_id, cancel_task
# The asset goes into a `Folder` asset that we own. `GEE._export_via_batch`
# writes the actual image at `<asset_id>/<prefix>`, so `asset_id` here is
# the parent FOLDER (not the final image path). Both must be cleaned up.
_proj = ee.data._get_projects_path().removeprefix('projects/')
DEMO_FOLDER = f'projects/{_proj}/assets/earthlens-demo-land-cover-change'
print(f'demo folder: {DEMO_FOLDER}')
# Best-effort cleanup of leftover children from a previous run (so the
# folder is empty before we try to delete it below).
try:
for child in ee.data.listAssets({'parent': DEMO_FOLDER}).get('assets', []):
ee.data.deleteAsset(child['name'])
print(f'cleared leftover child: {child["name"]}')
ee.data.deleteAsset(DEMO_FOLDER)
print(f'cleared leftover folder: {DEMO_FOLDER}')
except Exception:
pass
# Create the parent folder — EE requires it to exist before a child write.
ee.data.createAsset({'type': 'Folder'}, DEMO_FOLDER)
print(f'created folder: {DEMO_FOLDER}')
demo folder: projects/earth-engine-415620/assets/earthlens-demo-land-cover-change
created folder: projects/earth-engine-415620/assets/earthlens-demo-land-cover-change
Submit¶
Same (asset_id, band, AOI, scale) request as the sync download above, just routed through export_via="asset" + wait_for_export=False. download() returns a TaskInfo per submitted bucket at the moment the task is queued — no blocking.
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submitted_ok = False
task_info = None
try:
async_gee = GEE(
start='2021-01-01',
end='2021-12-31',
variables={'ESA/WorldCover/v200': ['Map']},
lat_lim=[29.9, 30.1],
lon_lim=[31.1, 31.3],
temporal_resolution='raw',
path=str(OUT_DIR),
service_account=SERVICE_ACCOUNT,
service_key=SERVICE_KEY,
scale=30.0,
reducer='mosaic',
export_via='asset',
asset_id=DEMO_FOLDER,
wait_for_export=False,
)
submitted = async_gee.download(progress_bar=False)
task_info = submitted[0]
submitted_ok = True
print(f'submitted: id={task_info.id} state={task_info.state}')
print(f' description={task_info.description}')
except Exception as exc:
if False:
print(f'async submission failed (tolerated): {type(exc).__name__}: {exc}')
else:
raise
submitted_ok = False
task_info = None
try:
async_gee = GEE(
start='2021-01-01',
end='2021-12-31',
variables={'ESA/WorldCover/v200': ['Map']},
lat_lim=[29.9, 30.1],
lon_lim=[31.1, 31.3],
temporal_resolution='raw',
path=str(OUT_DIR),
service_account=SERVICE_ACCOUNT,
service_key=SERVICE_KEY,
scale=30.0,
reducer='mosaic',
export_via='asset',
asset_id=DEMO_FOLDER,
wait_for_export=False,
)
submitted = async_gee.download(progress_bar=False)
task_info = submitted[0]
submitted_ok = True
print(f'submitted: id={task_info.id} state={task_info.state}')
print(f' description={task_info.description}')
except Exception as exc:
if False:
print(f'async submission failed (tolerated): {type(exc).__name__}: {exc}')
else:
raise
2026-05-18 00:17:07.415 | INFO | earthlens.gee.backend:_export_via_batch:833 - Submitted asset export L5R6HFCMB4S5LOSUK4VFQB4F (ESA_WorldCover_v200_Map_20210101); track via earthlens.gee.jobs.
submitted: id=L5R6HFCMB4S5LOSUK4VFQB4F state=READY
description=ESA_WorldCover_v200_Map_20210101
List + wait¶
list_recent_tasks(description_prefix=...) returns every matching task across the current project; wait_for_task_id blocks until the one we care about reaches a terminal state. A real workflow would just poll later from a separate process — the wait here exists so the notebook shows the full success path end-to-end.
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if submitted_ok and task_info is not None:
recent = list_recent_tasks(
description_prefix=task_info.description,
max_age_min=10,
)
print(f'list_recent_tasks matched {len(recent)} task(s):')
for t in recent:
print(f' {t.id} {t.state:<12} {t.description}')
try:
final = wait_for_task_id(
task_info.id, poll_seconds=10, progress_bar=False,
)
print(f'\nfinal state: {final.state}')
except RuntimeError as exc:
# Raised on FAILED / CANCELLED — cancel-if-still-running
# so we don't leak an in-flight task on notebook restart.
print(f'wait_for_task_id raised: {exc}')
try:
cancel_task(task_info.id)
except Exception:
pass
else:
print('Skipping list/wait — async submission did not succeed.')
if submitted_ok and task_info is not None:
recent = list_recent_tasks(
description_prefix=task_info.description,
max_age_min=10,
)
print(f'list_recent_tasks matched {len(recent)} task(s):')
for t in recent:
print(f' {t.id} {t.state:<12} {t.description}')
try:
final = wait_for_task_id(
task_info.id, poll_seconds=10, progress_bar=False,
)
print(f'\nfinal state: {final.state}')
except RuntimeError as exc:
# Raised on FAILED / CANCELLED — cancel-if-still-running
# so we don't leak an in-flight task on notebook restart.
print(f'wait_for_task_id raised: {exc}')
try:
cancel_task(task_info.id)
except Exception:
pass
else:
print('Skipping list/wait — async submission did not succeed.')
list_recent_tasks matched 1 task(s): L5R6HFCMB4S5LOSUK4VFQB4F READY ESA_WorldCover_v200_Map_20210101
final state: COMPLETED
Verify + clean up¶
Confirm the produced asset exists on Earth Engine, then delete it (and the surrounding demo folder) so we don't leak storage between notebook runs. The backend wrote the image at <DEMO_FOLDER>/<task description>.
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if submitted_ok and task_info is not None:
produced = f'{DEMO_FOLDER}/{task_info.description}'
try:
meta = ee.data.getAsset(produced)
print(f'asset exists: type={meta.get("type")} '
f'name={meta.get("name")}')
ee.data.deleteAsset(produced)
print('asset deleted')
except Exception as exc:
print(f'verify/delete skipped: {exc}')
# Always try to tear down the parent folder.
try:
ee.data.deleteAsset(DEMO_FOLDER)
print(f'folder deleted: {DEMO_FOLDER}')
except Exception as exc:
print(f'folder delete skipped: {exc}')
if submitted_ok and task_info is not None:
produced = f'{DEMO_FOLDER}/{task_info.description}'
try:
meta = ee.data.getAsset(produced)
print(f'asset exists: type={meta.get("type")} '
f'name={meta.get("name")}')
ee.data.deleteAsset(produced)
print('asset deleted')
except Exception as exc:
print(f'verify/delete skipped: {exc}')
# Always try to tear down the parent folder.
try:
ee.data.deleteAsset(DEMO_FOLDER)
print(f'folder deleted: {DEMO_FOLDER}')
except Exception as exc:
print(f'folder delete skipped: {exc}')
asset exists: type=IMAGE name=projects/earth-engine-415620/assets/earthlens-demo-land-cover-change/ESA_WorldCover_v200_Map_20210101
asset deleted
folder deleted: projects/earth-engine-415620/assets/earthlens-demo-land-cover-change
What's on disk¶
The GeoTIFF (or empty list, if the EE call was tolerated) is left under the per-notebook out/ directory for you to inspect. That directory is .gitignored — re-running the notebook overwrites it.
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for p in sorted(OUT_DIR.iterdir()) if OUT_DIR.exists() else []:
print(f'{p} ({p.stat().st_size / 1024:.1f} KB)')
for p in sorted(OUT_DIR.iterdir()) if OUT_DIR.exists() else []:
print(f'{p} ({p.stat().st_size / 1024:.1f} KB)')
out\land-cover-change\ESA_WorldCover_v200_Map_20210101.tif (53.3 KB)