Downloading with GEE

[1]:

# install with
# !pip install terragon-downloader[gee]

[ ]:

import terragon
import geopandas as gpd
import xarray as xr
import ee
from utils import visualize_sat_images, dict_to_tree

[2]:

# we will use the sample data to download a minicube
# other datasets are described here: https://developers.google.com/earth-engine/datasets
gdf = gpd.read_file("data/TUM_OTN.geojson")
arguments = dict(
    shp=gdf,
    collection="COPERNICUS/S2_SR_HARMONIZED",
    start_date="2021-01-01",
    end_date="2021-01-05",
    bands=["B2", "B3", "B4"],
    resolution=10,
    download_folder="tests/download/",
)
gdf.crs

[2]:

<Geographic 2D CRS: EPSG:4326>
Name: WGS 84
Axis Info [ellipsoidal]:
- Lat[north]: Geodetic latitude (degree)
- Lon[east]: Geodetic longitude (degree)
Area of Use:
- name: World.
- bounds: (-180.0, -90.0, 180.0, 90.0)
Datum: World Geodetic System 1984 ensemble
- Ellipsoid: WGS 84
- Prime Meridian: Greenwich

Initialize GEE

[3]:

# to authenticate you need to have an google account and be part of the google earth engine program
# register here: https://code.earthengine.google.com/register/

# ee.Authenticate() # authenticate if needed and not done before (providing credentials)
# usage of cloud projects are enforced in the future, see https://developers.google.com/earth-engine/guides/usage
ee.Initialize(opt_url="https://earthengine-highvolume.googleapis.com")
# ee.Initialize(opt_url='https://earthengine-highvolume.googleapis.com', project=<your_project>)

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[4]:

tg = terragon.init("gee")  # credentials are provided through ee.Authenticate()

Finding collections

[5]:

# This is not supported by GEE. Please, visit their website: https://developers.google.com/earth-engine/datasets
tg.retrieve_collections()

---------------------------------------------------------------------------
NotImplementedError                       Traceback (most recent call last)
Cell In[5], line 2
      1 # This is not supported by GEE. Please, visit their website: https://developers.google.com/earth-engine/datasets
----> 2 tg.retrieve_collections()

File ~/terragon_new_cdse/terragon/terragon/google_earth_engine.py:50, in GEE.retrieve_collections(self, filter_by_name)
     44 def retrieve_collections(self, filter_by_name: str = None) -> None:
     45     """Not implemented, because GEE does not have a collection endpoint.
     46
     47     :param filter_by_name: unused, kept for compatibility, defaults to None
     48     :raises NotImplementedError: GEE does not have a collection endpoint
     49     """
---> 50     raise NotImplementedError(
     51         "GEE does not have a collection endpoint. Please, visit https://developers.google.com/earth-engine/datasets/catalog"
     52     )

NotImplementedError: GEE does not have a collection endpoint. Please, visit https://developers.google.com/earth-engine/datasets/catalog

download (with geedim backend)

[5]:

# clipped tile tifs are downloaded with geedim and then merged into a single xarray dataset
ds = tg.create(**arguments, num_workers=10)
# or
# items = tg.search(**arguments, num_workers=10)
# ds = tg.download(items)
ds

[5]:

<xarray.Dataset> Size: 6kB
Dimensions:      (x: 28, y: 17, time: 2)
Coordinates:
  * x            (x) float64 224B 11.65 11.65 11.65 11.65 ... 11.66 11.66 11.66
  * y            (y) float64 136B 48.06 48.06 48.06 48.06 ... 48.05 48.05 48.05
  * time         (time) datetime64[ns] 16B 2021-01-01 2021-01-03
    spatial_ref  int64 8B 0
Data variables:
    B2           (time, y, x) uint16 2kB 0 0 0 0 0 0 0 0 0 ... 0 0 0 0 0 0 0 0 0
    B3           (time, y, x) uint16 2kB 0 0 0 0 0 0 0 0 0 ... 0 0 0 0 0 0 0 0 0
    B4           (time, y, x) uint16 2kB 0 0 0 0 0 0 0 0 0 ... 0 0 0 0 0 0 0 0 0
Attributes:
    crs:          EPSG:4326
    data_source:  GEE
    collection:   COPERNICUS/S2_SR_HARMONIZED

[6]:

visualize_sat_images(ds, gdf, list(reversed(arguments["bands"])))

[7]:

# the ouptut of the search is an ee ImageCollection
tg.search(**arguments)

[7]:

<ee.imagecollection.ImageCollection at 0x7ff8046fe110>

Special arguments for GEE

[8]:

# downloaded tile tifs are removed by default when creating a minicube, this behavior can be change with rm_tmp_files=False
ds = tg.create(**arguments, rm_tmp_files=False)