TY - GEN
T1 - A Comparison of Interpolation Techniques in Producing a DEM from the 5 m National Geospatial Institute (NGI) Contours
AU - Chetty, Prevlan
AU - Tesfamichael, Solomon
N1 - Publisher Copyright:
© 2021 by SCITEPRESS - Science and Technology Publications, Lda.
PY - 2021
Y1 - 2021
N2 - Continuous elevation surfaces, which are commonly referred to as Digital Elevation Models (DEM), are vital sources of information in flood modelling. Due to the multitude of interpolation techniques available to create DEMs, there is a need to identify the best suited interpolation techniques to represent a localised hydrological environment. This study investigated the accuracies of commonly applied interpolation techniques including Inverse Distance Weighting (IDW), Nearest Neighbour (NN), Kriging, Spline and Topo to Raster interpolation techniques as applied to a 5-m interval elevation contours as a precursor to simulate a flood zone in the Roodepoort region in Johannesburg, South Africa. A 50 cm resolution DEM derived from aerial Light Detection and Ranging (LiDAR) point cloud was used as a reference to compare the five interpolations techniques. The Topo to Raster results were not significantly different from the reference data (P = 0.79 at 95% confidence level), where elevation values were on average underestimated by 0.93 m. In contrast, the spline interpolation showed the highest significant difference from the reference data (P = 0.00 at 95% confidence level), with an average underestimation of the elevation by 69.84 m. Outlier identification using standardized residual analysis flagged significant elevation outliers that were produced in the interpolation process, and it was noted that most of the outliers across all techniques coincide with areas that showed frequent topographical changes. Specifically, the largest significant differences using the Topo to Raster technique were overestimations of the elevation that occur in the upstream section of the tributary. The Spline technique in contrast showed significant underestimations of the elevation throughout the river system. Overall, the results indicate that the Topo to Raster technique is preferred to accurately represent the topography around a river system of the study area.
AB - Continuous elevation surfaces, which are commonly referred to as Digital Elevation Models (DEM), are vital sources of information in flood modelling. Due to the multitude of interpolation techniques available to create DEMs, there is a need to identify the best suited interpolation techniques to represent a localised hydrological environment. This study investigated the accuracies of commonly applied interpolation techniques including Inverse Distance Weighting (IDW), Nearest Neighbour (NN), Kriging, Spline and Topo to Raster interpolation techniques as applied to a 5-m interval elevation contours as a precursor to simulate a flood zone in the Roodepoort region in Johannesburg, South Africa. A 50 cm resolution DEM derived from aerial Light Detection and Ranging (LiDAR) point cloud was used as a reference to compare the five interpolations techniques. The Topo to Raster results were not significantly different from the reference data (P = 0.79 at 95% confidence level), where elevation values were on average underestimated by 0.93 m. In contrast, the spline interpolation showed the highest significant difference from the reference data (P = 0.00 at 95% confidence level), with an average underestimation of the elevation by 69.84 m. Outlier identification using standardized residual analysis flagged significant elevation outliers that were produced in the interpolation process, and it was noted that most of the outliers across all techniques coincide with areas that showed frequent topographical changes. Specifically, the largest significant differences using the Topo to Raster technique were overestimations of the elevation that occur in the upstream section of the tributary. The Spline technique in contrast showed significant underestimations of the elevation throughout the river system. Overall, the results indicate that the Topo to Raster technique is preferred to accurately represent the topography around a river system of the study area.
KW - ANUDEM
KW - Chief Directorate National Geospatial Information
KW - GIS
KW - Interpolation
KW - Inverse Distance Weighting
KW - Kriging
KW - LiDAR
KW - Nearest Neighbour
KW - NGI
KW - Remote Sensing
KW - Spline
KW - Topo to Raster
UR - https://www.scopus.com/pages/publications/85137947946
M3 - Conference contribution
AN - SCOPUS:85137947946
T3 - International Conference on Geographical Information Systems Theory, Applications and Management, GISTAM - Proceedings
SP - 37
EP - 47
BT - GISTAM 2021 - Proceedings of the 7th International Conference on Geographical Information Systems Theory, Applications and Management
A2 - Grueau, Cedric
A2 - Laurini, Robert
A2 - Ragia, Lemonia
PB - Science and Technology Publications, Lda
T2 - 7th International Conference on Geographical Information Systems Theory, Applications and Management, GISTAM 2021
Y2 - 23 April 2021 through 25 April 2021
ER -
