Abstract
This paper describes a new approach for yield sampling in viticulture. It combines approaches based on auxiliary information and path optimization to offer more consistent sampling strategies, integrating statistical approaches with computer methods. To achieve this, groups of potential sampling points, comparable according to their auxiliary data values are created. Then, an optimal path is constituted that passes through one point of each group of potential sampling points and minimizes the route distance. This part is performed using constraint programming, a programming paradigm offering tools to deal efficiently with combinatorial problems. The paper presents the formalization of the problem, as well as the tests performed on nine real fields were high resolution NDVI data and medium resolution yield data were available. In addition, tests on simulated data were performed to examine the sensitivity of the approach to field data characteristics such as the correlation between auxiliary data and yield, the spatial auto-correlation of the data among others. The approach does not alter much the results when compared to conventional approaches but greatly reduces sampling time. Results show that, for a given amount of time, combining model sampling and path optimization can give estimation error up to 30% lower for a given amount of time compared to previous methods.