A field-intelligence studio for the High Plains

Quarter

We read farmland one quarter section at a time: what is planted, how it is growing, where it is stressed, and how many head stand in the pens.

Scroll to descend from 786 km to 70 m. Each altitude reads something the one above it cannot.

786 km

Two satellites, five days

Sentinel-2 is a pair of satellites on one orbit, phased 180° apart. Each comes back over the same field every 10 days; together, every 5 at the equator, more often at higher latitudes.

bands: 13: four at 10 m, six at 20 m, three at 60 m
red edge: B5, B6, B7 at 705, 740, 783 nm
near infrared: B8 at 842 nm, 10 m

Clouds are the first thing a pass has to see through, and an optical sensor cannot.

14 km

A mile, then a quarter

The land was surveyed before it was farmed. A section is a mile square, 640 acres; a quarter section is 160. A centre pivot sprinkler swings a circle inside a quarter, or across a whole section, from a single well.

In Finney County, Kansas, the circles are 800 and 1,600 m across, watered partly from the Ogallala Aquifer.

The survey lines draw first; the ground fills in after them.

5 km, 10 m pixels, B8 and B4

Vigour

Chlorophyll absorbs red light; leaf structure scatters near infrared. The difference, normalised, is the vegetation index:

NDVI = (NIR − Red) / (NIR + Red)

At 10 m an 800 m pivot is about 5,000 pixels: enough to see a dry arc, not a single plant.

2.6 km, 10 m pixels

Crop

The season’s curve gives each field away. USDA’s Cropland Data Layer classifies every field in the contiguous United States each year, at 30 m from 2008 to 2023 and at 10 m from 2024.

The classes here are ours: six colours, labelled where they grow.

corn
winter wheat
sorghum
alfalfa
soybeans
grass, fallow

1.1 km, 20 m pixels, B4, B5, B7

Stress

Crop disease changes how a canopy reflects the red edge. The red-edge bands B5 and B7 are native 20 m, so the pixel coarsens here. A Sentinel-2 index built on bands 4, 5 and 7 identified wheat yellow rust with 84.1% overall accuracy against field surveys.

Further out, satellites read the conditions pests need: soil moisture with vegetation flagged favourable swarming ground about 70 days before the November 2016 desert locust outbreak in Mauritania.

An alert is a place to send someone with boots, not a diagnosis.

70 m, 0.5 m pixels

Herd

At 10 m a steer covers under 2% of one pixel. At 50 cm, the resolution Pléiades delivers, it is four pixels long, and a model can count it. Published detectors already count cattle and elk on pasture this way.

—

head detected in this scene’s feedyard: a count of the render, not of a real yard.