Contour curvature is one of
the fundamental topographic indicators that reflects the convexities in the
horizontal direction of the topographical surface and expresses the divergence
and confluence patterns of the motion of the surface matters. Calculating the contour curvature can measure the
information conversion rate of the DEM interpolated by the vector contours, and provide a reference for setting the appropriate
DEM resolution. This study based on
vector contour data and DEM of Xiannangou watershed in Ansai County, Shaanxi Province, China, using the circle
fitting algorithms (adjacent three-point method, interval three-point method and least square method) and surface
fitting models (Evans model, Shary model and
Zevenbergen model) to calculate the contour curvature respectively. The comparative analysis between the real topography
of the site and the computational results indicated as follows: (1) The results
from the three-point fitting method
are different from the results using the least squares method, and the former describes the spatial pattern
distribution of the contour curvature more accurately. (2) The frequency
distribution of the results calculated by the least squares method is the
highest, and the difference
between the frequency curves of the two three-point fitting methods is small. (3) In the calculation
results of the DEM, the results from the
S-model display a larger difference than that by the E-model and the Z-model in the spatial pattern. The calculation results based on the E-model have a better effect on the contour curvature
description. The difference
presented by this paper when using different algorithms to calculate the
contour curvature provides important reference in retrieving the contour
curvature information in the practical digital terrain analysis.
WANG Ning, YAO Zhi-hong
. Extraction and analysis of the contour curvature based on different algorithms[J]. Arid Land Geography, 2020
, 43(1)
: 144
-152
.
DOI: 10.12118/j.issn.1000-6060.2020.01.17
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