Influence of DEM interpolation methods in Drainage Analysis

Influence of DEM interpolation methods in Drainage Analysis By: Manuel Peralvo

Outline • • Introduction Methods Results Conclusions

Introduction • Topography as a key landscape control • Availability of elevation information Objective • Evaluate the accuracy and influence of interpolation methods in the results of automated drainage analysis

Study Area

Methods • Data preparation • Four interpolation techniques: IDW, RBF, KRG, TOPOGRID • Modeled stream networks • Qualitative comparison • Quantitative comparison: Kappa coefficient

Methods • IDW and Kriging • Thin-plate spline RBF • TOPOGRID – Iterative – Drainage enforcement – Roughness penalty Source: Johnstotn et al. 2001

Methods • Kappa coefficient of agreement:

IDW RBF KRG TOPOGRID (DE) Results: Comparison Sector a TOPOGRID (WDE)

IDW RBF KRG TOPOGRID (DE) Results: Comparison Sector b TOPOGRID (WDE)

Results: Comparison of the AGREE DEMs

IDW KRG Results: Modeled and original contour lines RBF TOPOGRID (WDE)

Results Quantitative level of agreement Raw DEMs Reconditioned DEMs

Conclusions • Geostatistical methods: estimation of the accuracy of the prediction • Deterministic methods: time efficiency • TOPOGRID: adaptation to local topography • Quantitative evaluation of accuracy

Thank you