The applicability of concave hull algorithm in determination of seed distribution area

In this study, in addition to the methods of standard deviational ellipse (SDE), integral method (IM) and Voronoi polygons with Delaunay triangulation (VPDT) used to calculate the seed distribution area it is aimed to determine the efficiency of concave hull (CH) algorithm. In accordance with this purpose maize seeds were sown, seed distribution areas and their coefficients of variation were identified and statistically analyzed. Conventional tillage was utilized in the research. Sowing procedure was performed with a pneumatic sowing machine in three different forward speeds such as 1.5, 2 and 3 m·s-1. The research indicated that the increase in the tractor forward speed led to raise both the seed distribution area and its coefficient of variation. According to the results, it was observed that the concave hull method gave better results in comparison with the other methods mentioned. Concerning horizontal seed distribution areas for the forward speeds above, the best results were obtained using concave hull as follows: 15,243, 17,572, 24,864 mm2. For the vertical seed distribution areas, the best results were recorded as 186 mm2 with SDE at 1.5 m·s-1, 264 and 463 m·s-1 with CH at the speeds 2 and 3 m·s-1. The research concluded that concave hull algorithm can successfully be applied in calculation of seed distribution areas. When the analysis concerned with emergence investigated, seed emergence rate, mean seed emergence time, seed emergence index and plants per m2 were affected by the tractor forward speeds gradually. The highest seed emergence rate and plants per m2 were observed in the parcels sown at 1.5 m·s-1 speed.