Results - Response of Flood Events to Land Use and Climate Change - page 131

(a)

(b)

Contour Line
DEM

High : 1772

0 0.050.1 0.2 Kilometers

Low : 1069

Fig. 6.4 Typical spatial pattern of error. a Modeled DEM. b Original DEM

Table 6.2 Frequency distribution of DEM error

Deterministic Geostatistic

IDW Topo Spline Circular Exponential Gaussian Stable Spherical

Mean -3.55 -3.55 -3.55 -.000 -.003 -.000 -.024 -.000

Max 2.281 2.303 2.27 .000 .003 .000 .055 .000

R square .972 .972 .972 1.000 1.000 1.000 1.000 1.000

Table 6.3 Standard error and P value of significant level

Variable Standard coefficient Standard error P value

IDW 0.986 0.005 0.000

Topo 0.986 0.005 0.000

Spline 0.986 0.005 0.008

Circular 1 \.001 0.000

Exponential 1 \.001 0.000

Gaussian 1 \.001 0.000

Stable 1 \.001 0.000

Spherical 1 \.001 0.000

methods represent better results comparing to deterministic methods. The standard
error for all Circular, Exponential, Gaussian, Stable, and Spherical is \.001.
For Geostatistic methods, the standard error was about 0, which means that the
spatial distribution of points in applied methods is not too far from the distribution
of original values. When modeling elevation error, it is always assumed that error
is spatially autocorrelated.
This is a reasonable assumption given that the terrain tends to vary smoothly
rather than abruptly, so that the neighboring pixels are likely to have similar height