Fig 1.
Quadrangular Irregular Network.
Fig 2.
The quadrilateral with four corner points Pn,m, Pn,m+1, Pn+1,m, Pn+1,m+1 and the partial derivatives Rn,m, Tn,m on data point Pn,m.
Fig 3.
Peaks surface is function of three variables, obtained by translating and scaling Gaussian distributions, which is useful for DEM test.
(a) 3D display (b) 2D display.
Fig 4.
Distribution of both (a) the original data points and (b) the new ones.
Fig 5.
Distribution of all points.
Fig 6.
QIN constructed network and its magnified information.
Fig 7.
New points error distribution of simulations.
(a) IDW, (b) KRIGING, (c) SPLINE, (d) TIN.
Table 1.
RMSE and other information of new points employed simulation methods.
Fig 8.
Check points error distribution of simulations.
(a) QIN, (b) SPLINE, (c) KRIGING, (d) TIN.
Table 2.
RMSE and other information of check points employed simulation methods.
Fig 9.
Comparisons between new points errors and check points errors.
Table 3.
Pearson product-moment correlation coefficient among parameters.
Fig 10.
Location of elevation sampling points of Midu County.
(a) Points for DEM construction, (b) Points for inspecting DEM accuracy.
Fig 11.
Location and topography of Midu County.
Fig 12.
Comparisons between simulation results and observed data.
(a) SPLINE, (b) KRIGING, (c) TIN and (d) QIN.