Module Cubic Spline Approximation
This module approximates irregular scalar 2D data in specified points using C1-continuous bivariate cubic spline.
Minimal Number of Points: minimal number of points locally involved in spline calculation (normally = 3)
Maximal Number of Points:npmax: maximal number of points locally involved in spline calculation (required > 10, recommended 20 < npmax < 60)
Tolerance: relative tolerance multiple in fitting spline coefficients: the higher this value, the higher degree of the locally fitted spline (recommended 80 < k < 200)
Points per square: average number of points per square (increase if the point distribution is strongly non-uniform to get larger cells)
Author: Pavel Sakov, CSIRO Marine Research
Purpose: 2D data approximation with bivariate C1 cubic spline. A set of library functions + standalone utility.
Description: See J. Haber, F. Zeilfelder, O.Davydov and H.-P. Seidel, Smooth approximation and rendering of large scattered data sets, in 'Proceedings of IEEE Visualization 2001' (Th.Ertl, K.Joy and A.Varshney, Eds.), pp.341-347, 571, IEEE Computer Society, 2001.
www.uni-giessen.de/www-Numerische-Mathematik/davydov/VIS2001.ps.gz
www.math.uni-mannheim.de/~lsmath4/paper/VIS2001.pdf.gz
- Author: O. Conrad (c) 2008
- Specification: grid
- Menu: Grid|Gridding|Spline Interpolation
Parameters
Name | Type | Identifier | Description | Constraints | |
---|---|---|---|---|---|
Input | Points | Shapes (input) | SHAPES | - | - |
Target System (*) | Grid (optional input) | TARGET_TEMPLATE | use this grid's system for output grids | - | |
Output | Target Grid | Grid (output) | TARGET_OUT_GRID | - | - |
Options | Attribute | Table field | FIELD | - | - |
Target Grid System | Choice | TARGET_DEFINITION | - | Available Choices: [0] user defined [1] grid or grid system Default: 0 | |
Left | Floating point | TARGET_USER_XMIN | - | Default: 0.000000 | |
Right | Floating point | TARGET_USER_XMAX | - | Default: 100.000000 | |
Bottom | Floating point | TARGET_USER_YMIN | - | Default: 0.000000 | |
Top | Floating point | TARGET_USER_YMAX | - | Default: 100.000000 | |
Cellsize | Floating point | TARGET_USER_SIZE | - | Minimum: 0.000000 Default: 1.000000 | |
Fit | Choice | TARGET_USER_FITS | - | Available Choices: [0] nodes [1] cells Default: 0 | |
Minimal Number of Points | Integer | NPMIN | - | Minimum: 0 Default: 3 | |
Maximal Number of Points | Integer | NPMAX | - | Minimum: 11 Maximum: 59 Default: 20 | |
Points per Square | Floating point | NPPC | - | Minimum: 1.000000 Default: 5.000000 | |
Tolerance | Integer | K | Spline sensitivity, reduce to get smoother results, recommended: 80 < Tolerance < 200 | Minimum: 0 Default: 140 | |
(*) optional |
Command-line
Usage: saga_cmd grid_spline 6 [-SHAPES <str>] [-FIELD <str>] [-TARGET_DEFINITION <str>] [-TARGET_USER_XMIN <str>] [-TARGET_USER_XMAX <str>] [-TARGET_USER_YMIN <str>] [-TARGET_USER_YMAX <str>] [-TARGET_USER_SIZE <str>] [-TARGET_USER_FITS <str>] [-TARGET_TEMPLATE <str>] [-TARGET_OUT_GRID <str>] [-NPMIN <num>] [-NPMAX <num>] [-NPPC <str>] [-K <num>] -SHAPES:<str> Points Shapes (input) -FIELD:<str> Attribute Table field -TARGET_DEFINITION:<str> Target Grid System Choice Available Choices: [0] user defined [1] grid or grid system Default: 0 -TARGET_USER_XMIN:<str> Left Floating point Default: 0.000000 -TARGET_USER_XMAX:<str> Right Floating point Default: 100.000000 -TARGET_USER_YMIN:<str> Bottom Floating point Default: 0.000000 -TARGET_USER_YMAX:<str> Top Floating point Default: 100.000000 -TARGET_USER_SIZE:<str> Cellsize Floating point Minimum: 0.000000 Default: 1.000000 -TARGET_USER_FITS:<str> Fit Choice Available Choices: [0] nodes [1] cells Default: 0 -TARGET_TEMPLATE:<str> Target System Grid (optional input) -TARGET_OUT_GRID:<str> Target Grid Grid (output) -NPMIN:<num> Minimal Number of Points Integer Minimum: 0 Default: 3 -NPMAX:<num> Maximal Number of Points Integer Minimum: 11 Maximum: 59 Default: 20 -NPPC:<str> Points per Square Floating point Minimum: 1.000000 Default: 5.000000 -K:<num> Tolerance Integer Minimum: 0 Default: 140