Tool Multilevel B-Spline
Multilevel B-spline algorithm for spatial interpolation of scattered data as proposed by Lee, Wolberg and Shin (1997).
The algorithm makes use of a coarse-to-fine hierarchy of control lattices to generate a sequence of bicubic B-spline functions, whose sum approaches the desired interpolation function. Performance gains are realized by using B-spline refinement to reduce the sum of these functions into one equivalent B-spline function.
The 'Maximum Level' determines the maximum size of the final B-spline matrix and increases exponential with each level. Where level=10 requires about 1mb level=12 needs about 16mb and level=14 about 256mb(!) of additional memory.
References
- Lee, S., Wolberg, G., Shin, S.Y. (1997): Scattered Data Interpolation with Multilevel B-Splines. IEEE Transactions On Visualisation And Computer Graphics, Vol.3, No.3., p.228-244. ResearchGate.
- Author: O.Conrad (c) 2006
- Menu: Grid|Gridding|Spline Interpolation
Parameters
Name | Type | Identifier | Description | Constraints | |
---|---|---|---|---|---|
Input | Points | shapes, input | SHAPES | - | - |
Target System (*) | grid, input, optional, CMD | 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 | |
Cellsize | floating point number | TARGET_USER_SIZE | - | Minimum: 0.000000 Default: 1.000000 | |
West | floating point number | TARGET_USER_XMIN | - | Default: 0.000000 | |
East | floating point number | TARGET_USER_XMAX | - | Default: 100.000000 | |
South | floating point number | TARGET_USER_YMIN | - | Default: 0.000000 | |
North | floating point number | TARGET_USER_YMAX | - | Default: 100.000000 | |
Columns | integer number | TARGET_USER_COLS | Number of cells in East-West direction. | Minimum: 1 Default: 101 | |
Rows | integer number | TARGET_USER_ROWS | Number of cells in North-South direction. | Minimum: 1 Default: 101 | |
Fit | choice | TARGET_USER_FITS | - | Available Choices: [0] nodes [1] cells Default: 0 | |
Grid System | grid system | TARGET_SYSTEM | - | - | |
Refinement | choice | METHOD | - | Available Choices: [0] no [1] yes Default: 0 | |
Threshold Error | floating point number | EPSILON | - | Minimum: 0.000000 Default: 0.000100 | |
Maximum Level | integer number | LEVEL_MAX | - | Minimum: 1 Maximum: 14 Default: 11 | |
Update View | boolean, GUI | UPDATE | - | Default: 0 | |
(*) optional |
Command-line
Usage: saga_cmd grid_spline 4 [-SHAPES <str>] [-FIELD <str>] [-TARGET_DEFINITION <str>] [-TARGET_USER_SIZE <double>] [-TARGET_USER_XMIN <double>] [-TARGET_USER_XMAX <double>] [-TARGET_USER_YMIN <double>] [-TARGET_USER_YMAX <double>] [-TARGET_USER_COLS <num>] [-TARGET_USER_ROWS <num>] [-TARGET_USER_FITS <str>] [-TARGET_TEMPLATE <str>] [-TARGET_OUT_GRID <str>] [-METHOD <str>] [-EPSILON <double>] [-LEVEL_MAX <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_SIZE:<double> Cellsize floating point number Minimum: 0.000000 Default: 1.000000 -TARGET_USER_XMIN:<double> West floating point number Default: 0.000000 -TARGET_USER_XMAX:<double> East floating point number Default: 100.000000 -TARGET_USER_YMIN:<double> South floating point number Default: 0.000000 -TARGET_USER_YMAX:<double> North floating point number Default: 100.000000 -TARGET_USER_COLS:<num> Columns integer number Minimum: 1 Default: 101 -TARGET_USER_ROWS:<num> Rows integer number Minimum: 1 Default: 101 -TARGET_USER_FITS:<str> Fit choice Available Choices: [0] nodes [1] cells Default: 0 -TARGET_TEMPLATE:<str> Target System grid, input, optional, CMD -TARGET_OUT_GRID:<str> Target Grid grid, output -METHOD:<str> Refinement choice Available Choices: [0] no [1] yes Default: 0 -EPSILON:<double> Threshold Error floating point number Minimum: 0.000000 Default: 0.000100 -LEVEL_MAX:<num> Maximum Level integer number Minimum: 1 Maximum: 14 Default: 11