Read lightning data

Python ASCII file read functions could be used if the data can not be read by asciiread or DataFrame.read_table functions. Read data into several Python lists and create arrays from them for plotting.

fn = 'D:/Temp/ascii/lightning/2009_06_06.txt'
tf = open(fn)
lats = []
lons = []
vs = []
for aline in tf:
    datalist = aline.split()
    lat = float(datalist[3].split('=')[1])
    lon = float(datalist[4].split('=')[1])
    v = float(datalist[5].split('=')[1])
    lats.append(lat)
    lons.append(lon)
    vs.append(v)
lon = array(lons)
lat = array(lats)
v = array(vs)
axesm()
geoshow('cn_province')
ss = makesymbolspec('point', {'value':(-10000,0), 'color':'b', 'marker':'m', 'size':6, 'caption':'Negative'}, \
    {'value':(0,10000), 'color':'r', 'marker':'+', 'size':6, 'caption':'Positive'})
layer = scatter(lon, lat, v, symbolspec=ss)
legend(legend=layer.legend(), loc='lower left')
xlim(90, 130)
ylim(20, 50)
title('Lightning locations')