Table 1.
Characteristics of the UAV data collected over time. Days after planting (DAP), estimate potato growth stage (according to the BBCH scale [27,28]), growing degrees day (GDD; using 7 °C as base temperature), flight time (UTC +2), Sun zenith angle (SZA), Sun azimuth angle (SAA), and illumination conditions.
| Date | DAP | Growth Stage 1 | GDD 2 | Flight Time | SZA 3 | SAA 3 | Illum. |
|---|---|---|---|---|---|---|---|
| 05 June 2015 | 43 | 3–4 | 235.7 | 13:24 | 29.5 | 174.5 | Clear |
| 24 June 2015 | 62 | 4–5 | 368.9 | 09:49 | 52.0 | 100.4 | Overcast |
| 07 July 2015 | 75 | 6–7 | 541.7 | 10:16 | 49.0 | 106.6 | Clear |
| 16 July 2015 | 84 | 8–9 | 631.2 | 10:57 | 44.3 | 117.7 | Clear |
| 31 July 2015 | 99 | 9 | 774.7 | 12:15 | 37.9 | 144.3 | Clear |
1 BBCH scale: 3—main stem elongation; 4—tuber formation; 5—inflorescence emerging; 6—flowering; 7—fruit development; 8—ripening of fruit and seed; 9—senescence. 2 calculated from daily maximum and minimum temperatures from an automated weather station locate at approx. 3 km from the experimental field (weather station “Veenkampen”, 51.9808° N, 5.6217° E); 3 SZA and SAA calculated in relation to the center of the images.