SAGA-GIS Tool Library Documentation (v7.7.0)

Tool Multilevel B-Spline (3D)

Multilevel B-spline algorithm for spatial interpolation of scattered data as proposed by Lee, Wolberg and Shin (1997) modified for 3D data.
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


Parameters

 NameTypeIdentifierDescriptionConstraints
InputPointsShapes, inputPOINTS--
Target System (*)Grid, input, optional, CMDTARGET_TEMPLATEuse this grid's system for output grids-
OutputGrid CollectionGrids, outputGRIDS--
OptionsZTable fieldZ_FIELD--
Z FactorFloating pointZ_SCALE-Minimum: 0.000000
Default: 1.000000
ValueTable fieldV_FIELD--
Target Grid SystemChoiceTARGET_DEFINITION-Available Choices:
[0] user defined
[1] grid or grid system
Default: 0
CellsizeFloating pointTARGET_USER_SIZE-Minimum: 0.000000
Default: 1.000000
WestFloating pointTARGET_USER_XMIN-Default: 0.000000
EastFloating pointTARGET_USER_XMAX-Default: 100.000000
SouthFloating pointTARGET_USER_YMIN-Default: 0.000000
NorthFloating pointTARGET_USER_YMAX-Default: 100.000000
ColumnsIntegerTARGET_USER_COLSNumber of cells in East-West direction.Minimum: 1
Default: 100
RowsIntegerTARGET_USER_ROWSNumber of cells in North-South direction.Minimum: 1
Default: 100
FitChoiceTARGET_USER_FITS-Available Choices:
[0] nodes
[1] cells
Default: 0
Grid SystemGrid systemTARGET_SYSTEM--
CellsizeFloating pointTARGET_USER_ZSIZE-Minimum: 0.000000
Default: 1.000000
BottomFloating pointTARGET_USER_ZMIN-Default: 0.000000
TopFloating pointTARGET_USER_ZMAX-Default: 100.000000
LevelsIntegerTARGET_USER_ZNUM-Minimum: 1
Default: 100
Threshold ErrorFloating pointEPSILON-Minimum: 0.000000
Default: 0.000100
Maximum LevelIntegerLEVEL_MAX-Minimum: 1
Maximum: 14
Default: 11
(*) optional

Command-line

Usage: saga_cmd grid_spline 8 [-POINTS <str>] [-Z_FIELD <str>] [-Z_SCALE <double>] [-V_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>] [-GRIDS <str>] [-TARGET_USER_ZSIZE <double>] [-TARGET_USER_ZMIN <double>] [-TARGET_USER_ZMAX <double>] [-TARGET_USER_ZNUM <num>] [-EPSILON <double>] [-LEVEL_MAX <num>]
  -POINTS:<str>              	Points
	Shapes, input
  -Z_FIELD:<str>             	Z
	Table field
  -Z_SCALE:<double>          	Z Factor
	Floating point
	Minimum: 0.000000
	Default: 1.000000
  -V_FIELD:<str>             	Value
	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, input, optional, CMD
  -GRIDS:<str>               	Grid Collection
	Grids, output
  -TARGET_USER_ZSIZE:<double>	Cellsize
	Floating point
	Minimum: 0.000000
	Default: 1.000000
  -TARGET_USER_ZMIN:<double> 	Bottom
	Floating point
	Default: 0.000000
  -TARGET_USER_ZMAX:<double> 	Top
	Floating point
	Default: 100.000000
  -TARGET_USER_ZNUM:<num>    	Levels
	Integer
	Minimum: 1
	Default: 100
  -EPSILON:<double>          	Threshold Error
	Floating point
	Minimum: 0.000000
	Default: 0.000100
  -LEVEL_MAX:<num>           	Maximum Level
	Integer
	Minimum: 1
	Maximum: 14
	Default: 11