Date of Graduation
Eberly College of Arts and Sciences
Geology and Geography
Unpersoned aerial systems (UAS) could provide winegrowers with the potential to monitor vineyard productivity with ultra-high-resolution imagery and low operational costs. This ability could prove particularly valuable in the challenging cool-climate viticultural areas of Appalachia. Especially in this mountainous region of increasingly variable microclimates, there could be of great value from an ability to use UAS-measured greenness to monitor wine grape phenology and predict harvest quality and quantity. In this study, I assess how UAS-measured greenness relates to three complementary measures of field-based: leaf angle measurements, phenocam measured greenness, and leaf spectral measurements of greenness. After correlating these field-based measures of greenness to UAS-measured greenness, I evaluate whether UAS-sensed greenness can predict spatial and temporal patterns in seasonal wine grape phenology.
I collected imagery every other week between June and September 2020 from a DJI Mavic 2 Pro UAS platform, focusing on three blocks of Marechal Foch varietal grapes at the Christian W. Klay Winery in Chalkhill, Pennsylvania. I also collect weekly leaf angle and greenness measurements from consumer-grade phenocams. From these data, I employed multivariate regression to assess the relationship of UAS-measured greenness to the three field-based measures of greenness. Based on these tests, I concluded that UAS-measured greenness is not highly correlated across space and time with field-based measures of greenness. I hypothesize this might be due to highly vertical leaf angles present on the grapes vines limiting the amount of assessable green area from the perspective of the UAS.
Hoheneder, Timothy J., "Evaluation of a Low-Cost UAS and Phenocams for Measuring Grapevine Greenness" (2021). Graduate Theses, Dissertations, and Problem Reports. 8245.