DataLab is a compact statistics package aiming at exploratory data analysis. Please visit the DataLab Web site for more information....


3D Surface Plot

Command: Visualisation -> 3D Surface Plot

The 3D surface plot allows to display three-dimensional curved surfaces which are estimated from a set of data points. Each data point is defined by three coordinates, x, y, and z. These data points may be (and usually will be) irregularly distributed across the x-y-plane. DataLab performs an automatic interpolation of the irregular data grid to estimate the 3D surface. This interpolation may be controlled by the type of interpolation (biquadratic regression or weighted Gaussian kernels), the number of neighbors used for the estimation, and a smoothing parameter (in the case of weighted Gaussian kernels).

Hint: The correct interpolation of the 3D surface from the given data is quite complicated and may result in vastly wrong surfaces if the used parameters are inapproriate. In order to detect such situations DataLab compares the range of the data of the Z axis to the range of the estimated values. If these values deviate more than 50% from the measured data, DataLab issues a warning message accross the 3D plot. In this case increasing the number of neighbors usually solves the problem.