| | |
- griddata(x, y, z, xi, yi, masked=False, fill_value=1e+30, **kwargs)
- zi = griddata(x,y,z,xi,yi,**kwargs) fits a surface of the form z = f(x,y)
to the data in the (usually) nonuniformly spaced vectors (x,y,z).
griddata interpolates this surface at the points specified by (xi,yi)
to produce zi.
xi and yi form a grid (usually produced by meshgrid).
and must be monotone increasing, but not necessarily uniformly spaced.
Uses a technique called "natural neighbor interpolation" (see e.g
Sibson, R., A Brief Description of Natural Neighbor Interpolation,
in Interpreting Multivariate Data, ed. by V. Barnett,
John Wiley & Sons, New York, 1981, pp. 21-36) as implemented
in the NCAR natgrid library (http://ngwww.ucar.edu/ngdoc/ng/ngmath/natgrid/nnhome.html).
Download: /people/jeffrey.s.whitaker/python/griddata-0.1.1.tar.gz
Parameters controlling interpolation (set in **kwargs)
(For more details see
http://ngwww.ucar.edu/ngdoc/ng/ngmath/natgrid/contents.html)
Parameter | parameter | | |
name | type | description | legal values | default value
| | | |
------------------------------------------------------------------------------
bI | float | tautness factor that| >= 1. | 1.5
| | increases the | |
| | effect of the | |
| | gradients as bI | |
| | increases. | |
------------------------------------------------------------------------------
bJ | float | tautness factor that| >= 1. | 7.0
| | decreases the | |
| | breadth of the | |
| | region affected by | |
| | the gradients. | |
------------------------------------------------------------------------------
dup | int | controls whether | 0 = no | 0
| | duplicate input | 1 = yes |
| | coordinates are | |
| | allowed. | |
------------------------------------------------------------------------------
ext | int | flags whether | 0 = no | 1
| | extrapolation is | 1 = yes |
| | allowed outside the | |
| | convex hull. | |
------------------------------------------------------------------------------
hor | float | Specifies the | >= 0. | 0.1*(extent of
| | amount of horizontal| | X values in
| | overlap to be | | output grid)
| | included outside of | |
| | the current region. | |
------------------------------------------------------------------------------
igr | int | flag indicating if | 0 = no | 0
| | nonlinear interp | 1 = yes |
| | is to be done. | |
-------------------------------------------------------------------------------
non | int | flags whether in- | 0 = yes | 0
| | terpolated values | 1 = no |
| | are allowed to be | |
| | negative. | |
------------------------------------------------------------------------------
nul | float | the value to be used| Any float | 0.0
| | on output for points| |
| | outside of the | |
| | convex hull when | |
| | extrapolation is not| |
| | allowed. | |
------------------------------------------------------------------------------
ver | float | Specifies the | >= 0. | 0.1*(extent of
| | amount of vertical | | Y values in the
| | overlap to be | | output grid)
| | included outside of | |
| | the current region. | |
------------------------------------------------------------------------------
if masked=True (default False), no extrapolation is done outside the
convex hull defined by the data points, and a masked array with a fill value
given by the 'fill_value' keyword (default 1.e30) is returned.
Equivalent to setting 'ext=0' and 'nul=fill_value' in **kwargs, and masking
the output values that are equal to fill_value.
Setting masked=True will override the values of ext and nul
specified in **kwargs.
|