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Automatic detection of dominant crop types in Poland based on satellite images

Pluto-Kossakowska Joanna, Pilarska Magdalena, Bartkowiak Paulina

Artificial Satellites : Journal of Planetary Geodesy

2020

Vol. 55, No. 4

185--208

The assumption of the European Union Common Agricultural Policy is to maintain good agricultural practices for sustainability in the environment. A number of requirements are imposed on farmers, including the maintenance of permanent grassland, fallow land or crop diversification. To meet these requirements, the European Union guarantees subsidies, but at the same time fields must be monitored focusing on crop identification. The limitation of field inspection and substituting it with crop recognition using satellite images could increase the effectiveness of this procedure. The application of satellite imagery in automatic detection and identification of dominant crops over a large area seems to be technically and economically sound. The paper discusses the concept and the results of automatic classification based on a Random Forests classifier performed on multitemporal images of Sentinel-2 and Landsat-8. A test site was established in a complex agricultural structure with long and narrow parcels in the south-eastern part of Poland. Time-series images acquired during the growing season 2016 were used for multispectral classification in different configurations: for Sentinel-2 and Landsat-8 separately and for both sensors integrated. Different Random Forests approaches and post-processing methods were examined based on independent data from farmers’ declarations records, reaching the best accuracy of over 90% for crops like winter or spring cereals. Overall accuracy of the classification ranged from 72% to 91% depending on the classification variant. The elaborated scheme is novel in the context of Polish complex agricultural structure and smallholders.

The problem of using and measurement of identifiable ground control points on high resolution aerial images

Kurczyński Zdzisław, Bakuła Krzysztof, Pilarska Magdalena, Ostrowski Wojciech

Archiwum Fotogrametrii, Kartografii i Teledetekcji

2019

vol. 31

135--144

This paper shows the influence of the selection of photogrammetric control points as natural, identifiable points instead of signalized, premarked control points on the results of aerial triangulation of high-resolution aerial images with GSD below 10 cm. In the experiment, different selections of controls were tested using point-type and linear-type points with measurement of their centre or corner. In the experiment, 2 blocks with GSD of 5 and 10 cm were selected using the same measurements in 4 tested approaches with sets of natural identifiable points used by comparing the result with the reference variant. The experiment proves the possibility of using natural controls instead of premarked controls for images of urban areas. This can significantly reduce the cost of photogrammetric missions in urban areas where it is easy to find uniquely identifiable control points that can be used for image orientation.

Artykuł ukazuje wpływ doboru osnowy fotogrametrycznej w postaci punktów naturalnych zamiast sygnalizowanych na wynik aerotriangulacji obrazów lotniczych o wysokiej rozdzielczości o pikselu rozmiaru poniżej 10 cm. W eksperymencie testowano dobór fotopunktu jako obiektu punktowego, liniowego, pomiaru jego środka lub narożnika. Eksperyment pozwala udowodnić możliwość stosowania osnowy naturalnej zamiast sygnalizowanej, co znacznie zmniejsza koszty misji fotogrametrycznych w obszarach urbanizowanych, w których łatwo znaleźć jednoznacznie identyfikowalnej punkty naturalne, mogące posłużyć orientacji obrazów lotniczych. W eksperymencie wykorzystano 2 bloku zdjęć o GSD 5 i 10 cm, dla których wykorzystano pomiary tych samych 4 zestawów osnowy naturalnej porównując wynik z wariantem referencyjnym.