Plotting irregular data without interpolation

Hi,

I have not found any documentation on plotting non regular data with
basemap *without* interpolation.
Plotting scattered data on the sphere works fine, but the size of each
point seems to be limited, so there are "holes".
Is there an option in basemap for that ?

Alexis

pcolor might be what you want (not pcolormesh()). I use it to plot radar data when there might be gaps in the coverage.

Ben Root

···

On Wed, Feb 1, 2012 at 9:59 AM, Alexis Praga <alexis.praga@…185…> wrote:

Hi,

I have not found any documentation on plotting non regular data with

basemap without interpolation.

Plotting scattered data on the sphere works fine, but the size of each

point seems to be limited, so there are “holes”.

Is there an option in basemap for that ?

Alexis

To do this you will have to bin your data into rectangular grid
boxes, filling a masked array (with the grid boxes that have no data
masked). There’s some code to this at

-Jeff
···

http://www.scipy.org/Cookbook/Matplotlib/Gridding_irregularly_spaced_data

-- Jeffrey S. Whitaker Phone : (303)497-6313
Meteorologist FAX : (303)497-6449
NOAA/OAR/PSD R/PSD1 Email : 325 Broadway Office : Skaggs Research Cntr 1D-113
Boulder, CO, USA 80303-3328 Web :

Jeffrey.S.Whitaker@…259…http://tinyurl.com/5telg

and here’s an example of how to do this with the matplotlib hexbin
function…

from numpy.random import uniform

import matplotlib.pyplot as plt

import numpy as np

from mpl_toolkits.basemap import Basemap

npts = 5000

m = Basemap(lon_0=270, boundinglat=20, projection='npstere')

# create randomly distributed points in map projection coordinates

x = uniform(m.xmin,m.xmax,npts)

y = uniform(m.ymin,m.ymax,npts)

xscaled = 4.*(x-0.5*(m.xmax-m.xmin))/m.xmax

yscaled = 4.*(y-0.5*(m.ymax-m.ymin))/m.ymax

# z is the data to plot at those points.

z = xscaled*np.exp(-xscaled**2-yscaled**2)

CS = plt.hexbin(x,y,C=z,gridsize=50,cmap=plt.cm.jet)

m.drawcoastlines()

m.drawparallels(np.arange(0,81,20))

m.drawmeridians(np.arange(-180,181,60))

m.colorbar() # draw colorbar

plt.show()

-Jeff
···

http://www.scipy.org/Cookbook/Matplotlib/Gridding_irregularly_spaced_data

-- Jeffrey S. Whitaker Phone : (303)497-6313
Meteorologist FAX : (303)497-6449
NOAA/OAR/PSD R/PSD1 Email : 325 Broadway Office : Skaggs Research Cntr 1D-113
Boulder, CO, USA 80303-3328 Web :

Jeffrey.S.Whitaker@…259…http://tinyurl.com/5telg