since the independent data are # Gaussian distributed, we expect a 2D Gaussian. colorbar () # now show the number of points in each bin. imshow ( grid, extent = extent, cmap = palette, origin = 'lower', vmin = zmin, vmax = zmax, aspect = 'auto', interpolation = 'bilinear' ) plt. first plot is x, y vs z, where z is a filled level plot. set_under ( alpha = 0.0 ) # plot the results. filter our nans which are in the grid zmin = grid. griddata ( x, y, z, binsize = binsize ) # see this routine's docstring # minimum values for colorbar. binsize = 0.3 grid, bins, binloc = griddata. the binsize is the width and height of one of the grid # cells, or bins in units of x and y. imagine drawing a symmetrical grid over the # plot above. we could represent the z data # as a third axis by either a 3d plot or contour plot, but we need to # grid it first. ylabel ( 'Z' ) # now show the dependent data (x vs y). ion () # pyplot interactive mode on # x vs z cross-section. # We expect it to be symmetric about and and y, attain a minimum on # the origin and display minor Gaussian noise. our # function is a symmetric, upward opening paraboloid z = x**2 + y**2. normal ( scale = 1.0, size = npts ) # add a good amount of noise z = zorig + noise # z = f(x, y) = x**2 + y**2 # plot some profiles / cross-sections for some visualization. zorig = x ** 2 + y ** 2 # z is a function of the form z = f(x, y). normal ( size = npts ) # create some normally distributed dependent data in x. Import numpy as np import matplotlib.pyplot as plt import griddata npr = np.
# return the grid if retbin : if retloc : return grid, bins, wherebin else : return grid, bins else : if retloc : return grid, wherebin else : return grid median ( bin ) grid = binval else : grid = np. bin = z if retloc : wherebin = ind if retbin : bins = bin. # find the position that xc and yc correspond to. for row in range ( nrow ): for col in range ( ncol ): xc = xi # x coordinate. copy ( grid ) # create list in same shape as grid to store indices if retloc : wherebin = np. arange ( ymin, ymax + binsize, binsize ) xi, yi = np. arange ( xmin, xmax + binsize, binsize ) yi = np. Revisions - ccampo Initial version """ # get extrema values. wherebin : list (2D) A 2D list the same shape as `grid` and `bins` where each cell contains the indicies of `z` which contain the values stored in the particular bin. bins : ndarray (2D) A grid the same shape as `grid`, except the value of each cell is the number of points in that bin. The value of each cell is the median value of the contents of the bin. Returns - grid : ndarray (2D) The evenly gridded data. retloc : boolean, optional Function returns `wherebins` variable (see below for description) if set to True. retbin : boolean, optional Function returns `bins` variable (see below for description) if set to True. This is the step in both directions, x and y. If each bin is a cube, then this is the x and y dimension.
Scipy griddata full#
binsize : scalar, optional The full width and height of each bin on the grid. z : ndarray (1D) The dependent data in the form z = f(x,y). y : ndarray (1D) The idependent data y-axis of the grid. Parameters - x : ndarray (1D) The idependent data x-axis of the grid. # griddata.py - ccampo import numpy as np def griddata ( x, y, z, binsize = 0.01, retbin = True, retloc = True ): """ Place unevenly spaced 2D data on a grid by 2D binning (nearest neighbor interpolation). Griddata function, as both produce similar results. The is essentially an Occam's Razor approach to the matplotlib.mlab
These can be further used for interpolation
Value represents the number of points in that bin and another in whichĮach bin contains the indices of the original dependent array which areĬontained in that bin.
Scipy griddata code#
Of that, the code also returns two other grids, one where each binned This function takes three 1D arrays, namely two independent dataĪrrays and one dependent data array and bins them into a 2D grid. Example 3 ¶Ī less robust but perhaps more intuitive method is presented in the codeīelow. To interpolate/smooth scattered data in n dimensions. The radial basis function module in the scipy sandbox can also be used The natgrid algorithm is aīit more robust, but cannot be included in matplotlib proper because of Instead of delaunay to do the interpolation. Once that is installed, the griddata function will use it
Scipy griddata install#
You run into one of those cases, you can install the matplotlib natgrid Unfortunately, theĭelaunay package is known to fail for some nearly pathological cases. Matplotlib) to do the natural neighbor interpolation. By default, griddata uses the scikits delaunay package (included in