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Hello,
I would like to ask for some hints
and help. I am currently trying to plot a "pseudo contour" over a Basemap. This contour is confined by borders obtained from a shapefile. I can generate the contour, I can retrieve the shapefile and put them on a basemap. What I have not been able to do is to limit the contour plot such that it only fills the area defined by a shapefile (in my case it is bordered by Province Lampung). You can use different shapefile for example, as the point of my question is how to limit contour fill by a shapefile.
Shapefile can be downloaded from http://www.gadm.org/data/shp/IDN_adm.zip
The generated figure can be found here:
https://lh3.googleusercontent.com/-hMlwe6MAjdc/Tf6HlxYxn1I/AAAAAAAAAEY/exdzSv30ZL4/s640/to_matplotlib_userlists.png
Thanks for the help!
--
Lukmanul Hakim
Here's the code:
----------------
from pylab import cm
import matplotlib.pyplot as plt 
import numpy as np
from mpl_toolkits.basemap import Basemap
#Define area about Province Lampung
ulat, llat, ulon, llon = -2.5, -6.5, 107, 103
m = Basemap(projection='merc', lon_0=0.0, llcrnrlon=llon,
 llcrnrlat=llat, urcrnrlon=ulon, urcrnrlat=ulat,
 resolution='i')
#Read shapefile of Province Lampung
s = m.readshapefile('E:/Works/UNILA/Research/IDN_adm/LampungMap/LampungMap', 'lampung')
#Define area for contour plot
llon1,ulon1 = 103,106
llat1,ulat1 = -6,-3.5
#Generate random data
nx,ny=5,5
data2 = np.random.sample((ny,nx))
x = np.linspace(llon1, ulon1, nx) 
y = np.linspace(llat1, ulat1, ny)
X,Y = np.meshgrid(x,y)
px,py = m(X,Y)
m.contourf(px, py, data2, cmap=cm.jet)
m.drawcoastlines()#(linewidth=0.5)
m.drawparallels(np.arange(-6.5,-2.5,1.),labels=[1,0,0,0],color='black',dashes=[1,0],labelstyle='+/-',linewidth=0.2) # draw parallels
m.drawmeridians(np.arange(102.,108.,1.),labels=[0,0,0,1],color='black',dashes=[1,0],labelstyle='+/-',linewidth=0.2) # draw meridians
plt.show()

I am having trouble adding minor tick marks to an auto-scaled axis on a linear plot. I hope someone can help.
I am drawing a plot where the X axis values are predictable, so I have the ability to define the desired major/minor intervals for tickmarks and gridlines. The scale of the X axis is automatically defined by matplotlib. I have manually specified the major and minor X axis tick/grid intervals using:
plt.grid(True, which='both')
XmajorLocator
XmajorFormatter
XminorLocator
My Y axis values are not predictable, so I rely on matplotlib to autoscale the Y axis, automatically defining the total range of values plotted and the major tickmark & gridline intervals. I need more gridline resolution, so I would like to be able to add minor gridlines to the automatically scaled Y axis, but I'm having trouble doing it.
At present the autoscaled Y axis is only producing major ticks and major gridlines. I'd like to add minor ticks and gridlines, but I have not been successful so far. I'm hoping that someone can point out an obvious solution that I've just overlooked. TIA.