OTN Gliders (basic plotting)

Gliders are Autonomous Underwater Vehicles that carry several oceanographic instruments and allow unmanned ocean sampling. Below we present code to simple plotting using data from the OTN Ocean Glider Programme.

glider_basic

Note that this particular glider adds a “zero” every time it starts a up-cast.

import csv
import matplotlib.pyplot as plt
import matplotlib.dates as md
import datetime
import urllib2
import StringIO
 
# Retreive data from the "glider" server
response = urllib2.urlopen('http://glider.ceotr.ca/data/live/sci_water_temp_live.csv')
data = response.read()
data = StringIO.StringIO(data)
 
# Read file
r = csv.DictReader(data)
 
# Initialize empty variables
date, lat, lon, depth, temp = [],[],[],[],[]
 
# Loop to parse data into our variables
for row in r:
    date.append(float(row['unixtime']))
    lat.append(float(row['lat']))
    lon.append(float(row['lon']))
    depth.append(float(row['depth']))
    temp.append(float(row['sci_water_temp']))
 
# Change unix-time into a date object (for easy plotting)
DATE = []
for row in date:
    DATE.append(datetime.datetime.fromtimestamp(row))
 
# Make plot
fig, ax1 = plt.subplots(1)
plt.scatter(DATE,depth,s=15,c=temp,marker='o', edgecolor='none')
plt.ylim((-0.5,max(depth)+5))
ax1.set_ylim(ax1.get_ylim()[::-1])
cbar = plt.colorbar(orientation='horizontal', extend='both')
xfmt = md.DateFormatter('%Hh\n%dd\n%b')
ax1.xaxis.set_major_formatter(xfmt)
cbar.ax.set_xlabel('Temperature ($^\circ$C)')
plt.title('Glider transect')
plt.ylabel('Depth (m)')
plt.show()
 
# Save figure (without 'white' borders)
plt.savefig('glider_basic.png', bbox_inches='tight')
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