Fuente: Wipo "precision farming" A method for deriving geo-referenced spatial yield data for an agricultural crop includes the steps of providing a plurality of containers C, in which the crop can be harvested and a plurality of first and second markers M,i, Mif, associated with each container. The first marker is placed at a location corresponding to the starting point for the harvesting of the crop and the second marker is placed at a location corresponding with the finishing point for the harvesting of the crop for that container. The yield for a section of the crop between markers M, and Mif is the weight of the crop harvested in that container divided by the area of that section denoted by the markers Ms, and Mf. The area is the distance between the markers and Mir times one half of the width of the rows in which the crop is grown. By combining the weight and area data (ie yield) with location data for the markers and Mif geo-reference spatial yield data is obtained. This data can be mapped using conventional yield mapping software. The method is particularly useful for hand-picked crops.