Accuracy and Effort of Interpolation and Sampling: Can GIS Help Lower Field Costs?

Abstract

Sedimentation is a problem for all reservoirs in the Black Hills of South Dakota. Before working on sediment removal, a survey on the extent and distribution of the sediment is needed. Two sample lakes were used to determine which of three interpolation methods gave the most accurate volume results. A secondary goal was to see if fewer samples could be taken while still providing similar results. The smaller samples would mean less field time and thus lower costs. Subsamples of 50%, 33% and 25% were taken from the total samples and evaluated for the lowest Root Mean Squared Error values. Throughout the trials, the larger sample sizes generally showed better accuracy than smaller samples. Graphing the sediment volume estimates of the full sample, 50%, 33% and 25% showed little improvement after a sample of approximately 40%-50% when comparing the asymptote of the separate samples. When we used smaller subsamples the predicted sediment volumes were normally greater than the full sample volumes. It is suggested that when planning future sediment surveys, workers plan on gathering data at approximately every 5.21 meters. These sample sizes can be cut in half and still retain relative accuracy if time savings are needed. Volume estimates may slightly suffer with these reduced samples sizes, but the field work savings can be of benefit. Results from these surveys are used in prioritization of available funds for reclamation efforts.

Comparison of Spatial Interpolation Techniques Using Visualization and Quantitative Assessment

“…They reported that no single method was suitable for all situations. Simpson and Wu [29] compared IDW, kriging, and spline on interpolating lake depth, and reported that spline produced the most accurate results with less than the ideal amount of sampled points.…”

A Hybrid Method for Interpolating Missing Data in Heterogeneous Spatio-Temporal Datasets

“…Nearly all instrumental space-time data are influenced by missing data [1,2]. Before data analysis, missing data must be well handled.…”

Seabed sediment volume computations using single beam echo sounder with dual frequencies based on different interpolation methods

“…For several marine based studies, sedimentation and its distribution should be determined accurately before working on sediment removal (Simpson and Wu, 2014) related to the construction matters. To determine the sedimentation, bathymetrical surveys with low and high frequencies allow estimating the thickness of sediment layer.…”