Satellite (NDVI)

Every few days the Sentinel-2 satellite photographs your parcels, and Elf turns those images into plant health (NDVI), water and moisture figures. You get a map of the vineyard from the day of the pass, the trend across the season and a clear view of which parcel stands out. The imagery comes from the European Copernicus programme and is free - all you need is a free account.

What you see on the screen

• ✓ An NDVI map and a true-colour image from the day of the pass, over an aerial base map, with your parcels outlined in white
• ✓ Per-parcel figures: NDVI (plant health), NDWI (water), NDMI (moisture) and cloud-free coverage
• ✓ A rating of each parcel against its own history from the same point of the season, plus its rank among the parcels in that pass
• ✓ The NDVI trend across the season and a season-to-season comparison on a shared axis, so you can see whether the vineyard starts earlier than last year
• ✓ Vigour zones inside a parcel - a split into a weaker, middle and stronger zone, with a GeoJSON or KML download for QGIS or Google Earth

How to set it up

• 1. Create a free Copernicus account and enter the Client ID and Client Secret in Settings › Sensors (IoT).
• 2. Draw the parcel boundaries in Parcels and rows - the satellite reads the figures from that exact outline, and parcels without a boundary are skipped.
• 3. When you open the Satellite (NDVI) screen, Elf checks for new imagery by itself. The first time it fetches the last 60 days, so the current season is there right away.
• 4. Earlier seasons are fetched on demand in the Past seasons panel at the bottom of the screen. Without them there is nothing yet to compare the current passes with.

What the satellite will not do

• - It will not notify you. The figures and the heatwave banner are there when you open the screen - Elf sends no text messages and no e-mails.
• - It will not show single vines. A pixel is 10 metres across, so it also covers the inter-row. For parcels under 0.5 ha and for narrow strips Elf labels the result Low reliability by itself.
• - It will not diagnose. The figure tells you which parcel to walk first; what is wrong with it you find out in the rows.
• - It will not calculate rates. Vigour zones are relative: they split that one parcel into three parts even when it is perfectly uniform.