Demo sources plugin

This example demonstrates the usage of sources plugins in earthkit-data.

We will use the earthkit-data-demo-source plugin, which allows accessing data from a SQL database. It has to be installed to make the exercise work.

# !pip install --quiet earthkit-data-demo-source

First, we create a test database.

import os
import sqlite3

import earthkit.data as ekd

DATA = [
    (50, 3.3, "2001-01-01 00:00:00", 4.9),
    (51, -3, "2001-01-02 00:00:00", 7.3),
    (50.5, -1.8, "2001-01-03 00:00:00", 5.5),
]


def make_db():
    if os.path.exists("_test.db"):
        os.unlink("_test.db")

    conn = sqlite3.connect("_test.db")
    c = conn.cursor()
    c.execute(
        """CREATE TABLE data(
                    lat NUMBER,
                    lon NUMBER,
                    time TEXT,
                    value NUMBER)"""
    )
    c.executemany("INSERT INTO data VALUES(?,?,?,?);", DATA)
    conn.commit()


make_db()

The plugin implements a new earthkit-data source called “demo-source”. We can simply use from_source() to read our database.

ds = ekd.from_source(
    "demo-source",
    "sqlite:///_test.db",
    "select * from data;",
    parse_dates=["time"],
)
df = ds.to_pandas()
df

	lat	lon	time	value
0	50.0	3.3	2001-01-01	4.9
1	51.0	-3.0	2001-01-02	7.3
2	50.5	-1.8	2001-01-03	5.5