Realización de Kriging ordinario en SAGA mediante el complemento SEXTANTE de QGIS

Question

Estoy intentando aprender a aplicar el análisis de kriging en QGIS utilizando el plug-in SEXTANTE y las herramientas SAGA. Parece que tengo mis carpetas SEXTANTE y SAGA configuradas correctamente según la guía del usuario. Nunca he utilizado una función de kriging antes y no puedo encontrar un buen recurso de SAGA que explique los diferentes parámetros de entrada. ¿Alguien tiene experiencia en el uso de la herramienta de kriging ordinaria en SAGA que pueda dar consejos o una referencia? Actualmente estoy recibiendo el siguiente mensaje de error en QGIS:

An error has occured while executing Python code: 
Traceback (most recent call last):   
File "C:/Documents and Settings/PS/.qgis/python/plugins\sextante\gui\ParametersDialog.py", line 137, in accept if self.setParamValues():   
File "C:/Documents and Settings/PS/.qgis/python/plugins\sextante\gui\ParametersDialog.py", line 91, in setParamValue if not self.setParamValue(param, self.paramTable.valueItems[param.name]):   
File "C:/Documents and Settings/PS/.qgis/python/plugins\sextante\gui\ParametersDialog.py", line 129, in setParamValue return param.setValue(widget.getValue())   
File "C:/Documents and Settings/PS/.qgis/python/plugins\sextante\parameters\ParameterExtent.py", line 11, in setValue if value is None: NameError: global name 'value' is not defined

Answer 1

Si nunca ha hecho kriging antes, debe entender lo que está haciendo. Si no es el caso, consiga un libro de texto sobre geoestadística. De todos modos, la mayoría de los parámetros están ahí para determinar el variograma:

johan@cdh7:~$ saga_cmd libgeostatistics_kriging 5
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library path:   /usr/lib/saga
library name:   libgeostatistics_kriging
module name :   Ordinary Kriging
author      :   (c) 2008 by O.Conrad
_____________________________________________
go...
Usage: 5 [-GRID <str>] [-VARIANCE <str>] -SHAPES <str> [-FIELD <str>] [-BVARIANCE] [-TARGET <str>] [-MODEL <str>] [-BLOCK] [-DBLOCK <str>] [-BLOG] [-NUGGET <str>] [-SILL <str>] [-RANGE <str>] [-LIN_B <str>] [-EXP_B <str>] [-POW_A <str>] [-POW_B <str>] [-MAXRADIUS <str>] [-NPOINTS_MIN <str>] [-NPOINTS_MAX <str>] [-USER_CELL_SIZE <str>] [-USER_FIT_EXTENT] [-USER_X_EXTENT_MIN <str>] [-USER_X_EXTENT_MAX <str>] [-USER_Y_EXTENT_MIN <str>] [-USER_Y_EXTENT_MAX <str>] [-SYSTEM_SYSTEM_NX <num>] [-SYSTEM_SYSTEM_NY <num>] [-SYSTEM_SYSTEM_X <str>] [-SYSTEM_SYSTEM_Y <str>] [-SYSTEM_SYSTEM_D <str>] [-GRID_GRID <str>] [-GRID_VARIANCE <str>]
  -GRID:<str>               Grid
    Data Object (optional output)
  -VARIANCE:<str>           Variance
    Data Object (optional output)
  -SHAPES:<str>             Points
    Shapes (input)
  -FIELD:<str>              Attribute
    Table field
  -BVARIANCE                Create Variance Grid
    Boolean
  -TARGET:<str>             Target Grid
    Choice
    Available Choices:
    [0] user defined
    [1] grid system
    [2] grid
  -MODEL:<str>              Variogram Model
    Choice
    Available Choices:
    [0] Spherical Model
    [1] Exponential Model
    [2] Gaussian Model
    [3] Linear Regression
    [4] Exponential Regression
    [5] Power Function Regression
  -BLOCK                    Block Kriging
    Boolean
  -DBLOCK:<str>             Block Size
    Floating point
    Minimum: 0.000000
  -BLOG                     Logarithmic Transformation
    Boolean
  -NUGGET:<str>             Nugget
    Floating point
    Minimum: 0.000000
  -SILL:<str>               Sill
    Floating point
    Minimum: 0.000000
  -RANGE:<str>              Range
    Floating point
    Minimum: 0.000000
  -LIN_B:<str>              Linear Regression
    Floating point
  -EXP_B:<str>              Exponential Regression
    Floating point
  -POW_A:<str>              Power Function - A
    Floating point
  -POW_B:<str>              Power Function - B
    Floating point
  -MAXRADIUS:<str>          Maximum Search Radius (map units)
    Floating point
    Minimum: 0.000000
  -NPOINTS_MIN:<str>        Min./Max. Number of m_Points
    Value range
  -NPOINTS_MAX:<str>        Min./Max. Number of m_Points
    Value range
  -USER_CELL_SIZE:<str>     Grid Size
    Floating point
    Minimum: 0.000000
  -USER_FIT_EXTENT          Fit Extent
    Boolean
  -USER_X_EXTENT_MIN:<str>  X-Extent
    Value range
  -USER_X_EXTENT_MAX:<str>  X-Extent
    Value range
  -USER_Y_EXTENT_MIN:<str>  Y-Extent
    Value range
  -USER_Y_EXTENT_MAX:<str>  Y-Extent
    Value range
  -SYSTEM_SYSTEM_NX:<num>   Grid System
    Grid system
  -SYSTEM_SYSTEM_NY:<num>   Grid System
    Grid system
  -SYSTEM_SYSTEM_X:<str>    Grid System
    Grid system
  -SYSTEM_SYSTEM_Y:<str>    Grid System
    Grid system
  -SYSTEM_SYSTEM_D:<str>    Grid System
    Grid system
  -GRID_GRID:<str>          Grid
    Grid (input)
  -GRID_VARIANCE:<str>      Variance
    Grid (optional input)