Assessment of Spatial Prediction Techniques Accuracy for Elevation Determination in Akure South Local Government, Ondo State

Adebayo T Adeboye,Victor Ayodele Ijaware

doi:10.24018/ejers.2020.5.5.1805

Abstract

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is a cooperative effort between NASA and Japan's Ministry of Economy Trade and Industry (METI), with the collaboration of scientific and industry organizations in both countries. The ASTER instrument provides a more robust remote sensing imaging capability when compared to the older Landsat Thematic Mapper. This paper deals with the accuracy assessment of elevation data obtained using ASTER from each of the eleven (11) selected extrapolation/interpolation algorithms: Inverse Distance Weighting, Natural Neighbor, Spline Regular, Spline Tension, Universal Kriging, Empirical Bayesian Kriging, Topo to Raster, global (trend surface), local polynomial, kernel interpolation with barriers and radial basis functions in Digital Elevation Model (DEM) surface creation. The data were compared with reference to ground control points of differential GPS measurements in the study area. The error statistics were generated between DGPS measurements and Extracted elevation data from each selected interpolation method. It was observed that Spline Regular Interpolation shown the best overall accuracy of ±11.520m when elevation data extracted from Inverse distance weighting, Natural Neighbour, Spline T, Topo to Raster, Universal Kriging, Empirical Bayesian kriging, Global polynomial interpolation (GPI), local polynomial interpolation (LPI), Radial basis function and Kernel interpolation of ±15.170, ±14.340, ±12.336, ±13.551, ±14.707, ±13.711, ±15.363, ±13.964, ±13.590 and ±15.376 respectively when compared with elevation values from GPS method. The study recommends capacity building in the form of workshop, training, and flexible integration of point elevation data to DEM.

Highlights

Elevation is a vital component in any geographic study utilized as a concrete measurement of the Earth’s surface above the sea level
Akure South Local Government Area was divided into fifteen units and Ground Control Points (GCPs) were established at a minimum of three kilometers interval from each other amounting to eighty-two established GCPs within the study area
Values from ASTER data source are relatively same using geospatial method of interpolation (Kriging) with the exception of the spatial interpolation methods (Natural, Spline and Topo to Raster) which does not have errors associated with the predicted points

Summary

Introduction

Elevation is a vital component in any geographic study utilized as a concrete measurement of the Earth’s surface above the sea level. Teams of surveyors historically collected elevation measurements, performing what is known as geodetic leveling [6]. Geodetic leveling measures the relative elevation from one area (usually the ocean or benchmark) to the area of interest. Digital Elevation Model (DEM) information for free, without financial costs of almost every region of the earth surface. These DEMs are dense and generally have good spatial distributions, the accuracy of their elevation information might not be suitable for many applications. A way of alleviating this problem is to combine the available DEM data along with other information, coming from reliable sources and having better quality, in the data modeling processes [2]

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