INTERNATIONAL JOURNAL OF ENGINEERING AND GEOSCIENCES, cilt.7, sa.2, ss.161-173, 2022 (ESCI)
Inverse
Distance Weighted (IDW) based interpolation method is also widely used in earth
science studies. in the classical IDW method, the directional distribution of
the reference points around the point to be estimated within the critical
circle and the slope differences are not taken into consideration. On the other
hand, in the IDW-based method developed by Shepard, the ratio of the distances
of the reference points within the critical circle to the critical circle
radius (r), the anisotropy and the slope differences are taken into
consideration. In this study, the results of the classical IDW method and
Shepard method were compared to increase the accuracy of interpolation produced
from UAV data. A software has been developed to make these comparisons in more
detail. The classical IDW and Shepard based interpolation methods used in this
software takes into consideration the anisotropy, the slope differences and the
ratio of the distances to the critical circle radius. In this study, UAV
flights were performed in three different study areas with different
topographic features and 3D point cloud data were obtained in order to make
detailed analyzes. Using developed software, data from three different study
areas have been tested and the results from different Shepard interpolation
models have been discussed. The major contribution of this paper is in
evaluation of various IDW options when applied to UAV point data. As a result,
especially in geodetic studies form UAV data, it was observed that the results
improved with 11% to 37% by using the Shepard method with the suitable power
parameter value considering the directional distribution of the reference
points in the critical circle and the slope differences.