Module Multilevel B-Spline Interpolation (from Grid)
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. Large 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.
Reference:
- 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
- Author: O.Conrad (c) 2006
- Specification: grid
- Menu: Grid|Gridding|Spline Interpolation
Parameters
| Name | Type | Identifier | Description | Constraints |
Input | Grid | Grid (input) | GRID | - | - |
Options | Method | Choice | METHOD | - | Available Choices: [0] without B-spline refinement [1] with B-spline refinement Default: 1 |
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 |
Data Type | Choice | DATATYPE | - | Available Choices: [0] same as input grid [1] floating point Default: 1 |
Command-line
Usage: saga_cmd grid_spline 5 -GRID <str> [-METHOD <str>] [-EPSILON <str>] [-LEVEL_MAX <num>] [-UPDATE <str>] [-DATATYPE <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>]
-GRID:<str> Grid
Grid (input)
-METHOD:<str> Method
Choice
Available Choices:
[0] without B-spline refinement
[1] with B-spline refinement
Default: 1
-EPSILON:<str> Threshold Error
Floating point
Minimum: 0.000000
Default: 0.000100
-LEVEL_MAX:<num> Maximum Level
Integer
Minimum: 1
Maximum: 14
Default: 11
-UPDATE:<str> Update View
Boolean
Default: 0
-DATATYPE:<str> Data Type
Choice
Available Choices:
[0] same as input grid
[1] floating point
Default: 1
-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)