sage interact tutorial on arctic icelevel

import urllib2, csv months = ['Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec'] longmonths = ['January','February','March','April','May','June','July','August','September','October','November','December'] @interact def iceplotter(month = selector(zip(range(1,13),longmonths),default = (4, 'April'),label="Month")): month_str = months[month-1] + '/N_%02d_area.txt'%(month) dialect=csv.excel dialect.skipinitialspace = True icedata_f = urllib2.urlopen('ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/%s'%month_str) cr = csv.reader(icedata_f,delimiter=' ', dialect=dialect) icedata = list(cr) icedata = [x for x in icedata[1:] if len(x)==6 and N(x[5])>0] lp = list_plot([[N(x[0]),N(x[4])] for x in icedata]) def lin_regress(xdata, ydata): xmean = N(mean(xdata)) ymean = N(mean(ydata)) xm = vector(RDF,[q-xmean for q in xdata]) ym = vector(RDF,[q-ymean for q in ydata]) xy = xm.inner_product(ym) xx = xm.inner_product(xm) slope = xy/xx intercept = ymean - slope*xmean return slope, intercept years = [N(x[0]) for x in icedata] ice = [N(x[4]) for x in icedata] slope, inter = lin_regress(years,ice) reg = plot(lambda x:slope*x+inter,(min(years),max(years))) html('<h3>Extent of Arctic sea ice coverage in %s, %d - %d</h3>'%(longmonths[month-1],min(years),max(years))) html('Data from the <a href="http://nsidc.org/">National Snow and Ice Data Center</a>') show(lp+reg, figsize = [7,4])