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 (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 |
| Cellsize | Floating point | TARGET_USER_SIZE | - | Minimum: 0.000000
Default: 1.000000 |
| West | Floating point | TARGET_USER_XMIN | - | Default: 0.000000 |
| East | Floating point | TARGET_USER_XMAX | - | Default: 100.000000 |
| South | Floating point | TARGET_USER_YMIN | - | Default: 0.000000 |
| North | Floating point | TARGET_USER_YMAX | - | Default: 100.000000 |
| Columns | Integer | TARGET_USER_COLS | Number of cells in East-West direction. | Minimum: 1
Default: 100 |
| Rows | Integer | TARGET_USER_ROWS | Number of cells in North-South direction. | Minimum: 1
Default: 100 |
| 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 | EPSILON | - | Minimum: 0.000000
Default: 0.000100 |
| Maximum Level | Integer | LEVEL_MAX | - | Minimum: 1
Maximum: 14
Default: 11 |
| Update View | Boolean | 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
Minimum: 0.000000
Default: 1.000000
-TARGET_USER_XMIN:<double> West
Floating point
Default: 0.000000
-TARGET_USER_XMAX:<double> East
Floating point
Default: 100.000000
-TARGET_USER_YMIN:<double> South
Floating point
Default: 0.000000
-TARGET_USER_YMAX:<double> North
Floating point
Default: 100.000000
-TARGET_USER_COLS:<num> Columns
Integer
Minimum: 1
Default: 100
-TARGET_USER_ROWS:<num> Rows
Integer
Minimum: 1
Default: 100
-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)
-METHOD:<str> Refinement
Choice
Available Choices:
[0] no
[1] yes
Default: 0
-EPSILON:<double> Threshold Error
Floating point
Minimum: 0.000000
Default: 0.000100
-LEVEL_MAX:<num> Maximum Level
Integer
Minimum: 1
Maximum: 14
Default: 11