FIRMS quickstart — recent active fires¶

Fetch recent active-fire detections (MODIS / VIIRS) from NASA FIRMS through the earthlens FIRMS backend, and plot the fire pixels coloured by fire radiative power (FRP).

FIRMS is a vector backend: download() returns a pyramids FeatureCollection (a geopandas.GeoDataFrame, CRS EPSG:4326), one row per fire pixel.

Setup¶

Pull in the imports up front: EarthLens is the unified entry point and matplotlib.pyplot is used for the final scatter. We also prepare an output directory — FIRMS is a file-writing-plus-in-memory vector backend, so download() writes the detections to firms_output/ and returns them as a GeoDataFrame.

In [ ]:

import datetime as dt
import os
from pathlib import Path

import matplotlib.pyplot as plt

from earthlens import EarthLens

OUT_DIR = Path('firms_output')
OUT_DIR.mkdir(exist_ok=True)

import datetime as dt import os from pathlib import Path import matplotlib.pyplot as plt from earthlens import EarthLens OUT_DIR = Path('firms_output') OUT_DIR.mkdir(exist_ok=True)

Credentials¶

FIRMS needs a free MAP_KEY (https://firms.modaps.eosdis.nasa.gov/api/map_key/). Set FIRMS_MAP_KEY in your environment; the live cells below skip cleanly when it is absent, so the notebook never fails offline.

In [ ]:

HAS_KEY = bool(os.environ.get('FIRMS_MAP_KEY'))
print('FIRMS_MAP_KEY set:', HAS_KEY)

HAS_KEY = bool(os.environ.get('FIRMS_MAP_KEY')) print('FIRMS_MAP_KEY set:', HAS_KEY)

Query¶

variables is a list of FIRMS sensor codes (not data variables). We use the 375 m VIIRS S-NPP near-real-time sensor over Southern California for a recent 7-day window. FIRMS caps requests at 10 days / one sensor, but the backend chunks longer windows transparently.

Date window¶

FIRMS near-real-time retains only the most recent ~2 months, so we anchor the window to a recent 7-day span ending today.

In [ ]:

TODAY = dt.date.today()
START = (TODAY - dt.timedelta(days=7)).strftime('%Y-%m-%d')
END = TODAY.strftime('%Y-%m-%d')

TODAY = dt.date.today() START = (TODAY - dt.timedelta(days=7)).strftime('%Y-%m-%d') END = TODAY.strftime('%Y-%m-%d')

Build the request and download¶

We build the EarthLens request first — source, sensor (variables), date window, bounding box, and output path — then call download() as a separate step. The whole thing stays inside a guard so the notebook skips cleanly when no MAP_KEY is set or the live query fails. The result is written to firms_output/ and returned in memory.

In [ ]:

fires = None
if HAS_KEY:
    try:
        request = EarthLens(
            data_source='firms',
            variables=['VIIRS_SNPP_NRT'],
            start=START,
            end=END,
            aoi=[-119.0, 33.0, -117.0, 35.0],
            path=str(OUT_DIR),
        )
        fires = request.download(progress_bar=False)
        print('detections:', len(fires))
    except Exception as exc:  # keep the notebook safe offline
        print('skipped live query:', exc)

fires = None if HAS_KEY: try: request = EarthLens( data_source='firms', variables=['VIIRS_SNPP_NRT'], start=START, end=END, aoi=[-119.0, 33.0, -117.0, 35.0], path=str(OUT_DIR), ) fires = request.download(progress_bar=False) print('detections:', len(fires)) except Exception as exc: # keep the notebook safe offline print('skipped live query:', exc)

Inspect the detections¶

Every row is one fire pixel with a normalised confidence_pct and frp (MW).

In [ ]:

if fires is not None and len(fires):
    cols = [
        'acq_datetime',
        'sensor',
        'confidence',
        'confidence_pct',
        'brightness_k',
        'frp',
        'daynight',
        'geometry',
    ]
    display(fires[cols].head())
    print('CRS:', fires.crs)

if fires is not None and len(fires): cols = [ 'acq_datetime', 'sensor', 'confidence', 'confidence_pct', 'brightness_k', 'frp', 'daynight', 'geometry', ] display(fires[cols].head()) print('CRS:', fires.crs)

Plot the fire pixels coloured by FRP¶

Plotting the GeoDataFrame directly with column='frp' colours each detection by its fire radiative power, so the most intense pixels stand out.

In [ ]:

if fires is not None and len(fires):
    ax = fires.plot(column='frp', cmap='inferno', markersize=18, alpha=0.7, legend=True)
    ax.set_title(f'FIRMS VIIRS detections, {START} to {END} (colour = FRP, MW)')
    ax.set_xlabel('longitude')
    ax.set_ylabel('latitude')
    plt.show()

if fires is not None and len(fires): ax = fires.plot(column='frp', cmap='inferno', markersize=18, alpha=0.7, legend=True) ax.set_title(f'FIRMS VIIRS detections, {START} to {END} (colour = FRP, MW)') ax.set_xlabel('longitude') ax.set_ylabel('latitude') plt.show()