Google Earth was
used in photo-interpretation for quality control and to verify the
field locations given in the ECS database. Geolocation of fields
was essential to create field- and crop-specific masks to overlay
information layers, in particular the spatially explicit potential
yield map and the satellite image-derived NDVI (see also Fig. 6).
For a subset of fields, ground observations on crop density, height
and leaf area (morphometric data) were also taken.