# Basemap and imshow

Is there a way of using imshow together with a basemap?

Cheers
Tommy

Tommy Grav wrote:

Is there a way of using imshow together with a basemap?

Cheers
Tommy

Tommy:

Use the imshow basemap method, just as you would the pylab version.

-Jeff

···

--
Jeffrey S. Whitaker Phone : (303)497-6313
NOAA/OAR/CDC R/PSD1 FAX : (303)497-6449
325 Broadway Boulder, CO, USA 80305-3328

Thanks for pointing this function out. I thought I had look for it, but must have overlooked it.

I am using the test code below, but the array is plotted outside the boundary of the map. Is there
a way to avoid this?

Cheers
Tommy

from math import *
from matplotlib.toolkits.basemap import Basemap
import pylab
import numpy

rabins = numpy.arange(0.,360.,6)
decbins = numpy.arange(-90.,90.,6)
map = Basemap(projection="sinu",lat_0=0.,lon_0=180.,rsphere=1.)

coverage = numpy.zeros([len(decbins),len(rabins)],"int")

coverage[0:5,:] = 2
coverage[5:10,:] = 4

map.imshow(coverage,interpolation="nearest",cmap=pylab.cm.hot_r)
map.drawmapboundary()

pylab.show()

···

On Mar 6, 2008, at 11:10 AM, Jeff Whitaker wrote:

Tommy Grav wrote:

Is there a way of using imshow together with a basemap?

Cheers
Tommy

Tommy:

Use the imshow basemap method, just as you would the pylab version.

-Jeff

--
Jeffrey S. Whitaker Phone : (303)497-6313
NOAA/OAR/CDC R/PSD1 FAX : (303)497-6449
325 Broadway Boulder, CO, USA 80305-3328

Tommy Grav wrote:

Thanks for pointing this function out. I thought I had look for it, but must have overlooked it.

I am using the test code below, but the array is plotted outside the boundary of the map. Is there
a way to avoid this?

Cheers
Tommy

from math import *
from matplotlib.toolkits.basemap import Basemap
import pylab
import numpy

rabins = numpy.arange(0.,360.,6)
decbins = numpy.arange(-90.,90.,6)
map = Basemap(projection="sinu",lat_0=0.,lon_0=180.,rsphere=1.)

coverage = numpy.zeros([len(decbins),len(rabins)],"int")

coverage[0:5,:] = 2
coverage[5:10,:] = 4

map.imshow(coverage,interpolation="nearest",cmap=pylab.cm.hot_r)
map.drawmapboundary()

pylab.show()

Tommy Grav wrote:

Is there a way of using imshow together with a basemap?

Cheers
Tommy

Tommy:

Use the imshow basemap method, just as you would the pylab version.

-Jeff

Tommy: You're using a non-rectangular map projection, so imshow won't work. Try pcolor or pcolormesh instead, i.e. replace map.imshow with:

rabins, decbins = numpy.meshgrid(rabins, decbins)
x,y = map(rabins,decbins)
map.pcolor(x,y,coverage,cmap=pylab.cm.hot_r)

-Jeff

···

On Mar 6, 2008, at 11:10 AM, Jeff Whitaker wrote:

--
Jeffrey S. Whitaker Phone : (303)497-6313
NOAA/OAR/CDC R/PSD1 FAX : (303)497-6449
325 Broadway Boulder, CO, USA 80305-3328