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Class 24: Python - parsing binary data 4 - SBET IMU data

Table of Contents

Please do not

update until the professor asks you to.

Introduction

Goals

  • [X] using argparse to handle the command line
  • [X] saving binary data to matlab format. Read it in octave
  • [X] using numpy to save the file
  • [X] writing a KML
  • [X] creating an SQL database with sqlite3. Viewing it with SQLite Manager

See Also

What is GIS?

Now that you have been doing Geographic Information System (GIS) tasks for quite a few classes, let me share with you how I view GIS. This figure is not perfect and is a gross oversimplification, but it is useful. The goal of GIS is "Informed Decision Making", which in NOAA equates to Coastal and Marine Spatial Planning (CMSP), safely navigating ships and many other decision making processes.

What is GIS?

Setup

Start emacs

Open a terminal and start ipython

In the past, we did the setup in the bash shell, but we can do everything from ipython. 

# update your mercurial repository of the class notes
cd ~/projects/researchtools/class
bookmark -l
bookmark hgclass # Save this for next class
bookmark -l

ls -l > ~/before.txt
!hg pull
!hg update
ls -l > ~/after.txt
!diff --unified ~/before.txt ~/after.txt
# You will see nothing if you already updated everything for today's classxs

mkdir ~/class/24
cd ~/class/24
bookmark c24
bookmark -l

cd hgclass
pwd
cd c24
pwd

logstart -o -r log-class-24.py

dhist
cd -1
cd -2

alias
alias rtupdate (cd ~/projects/researchtools; hg pull; hg update)
store rtupdate 
alias
rtupdate

# Sadly, I don't know how to save an alias in a simple/clean fashion.
# "store" for aliases is broken in ipython 0.11
# http://stackoverflow.com/questions/8183986/saving-ipython-aliases

# Fetch the sbet file:

!curl -O http://vislab-ccom.unh.edu/~schwehr/Classes/2011/esci895-researchtools/examples/21/sample.sbet.bz2
!curl -O http://vislab-ccom.unh.edu/~schwehr/Classes/2011/esci895-researchtools/examples/24/2010_202_S220_subsampled.sbet.bz2
!curl -O http://vislab-ccom.unh.edu/~schwehr/Classes/2011/esci895-researchtools/examples/24/2011_194_S250A_Stbd_subsampled.sbet.bz2

!bunzip2 sample.sbet.bz2
!bunzip2 2010_202_S220_subsampled.sbet.bz2
!bunzip2 2011_194_S250A_Stbd_subsampled.sbet.bz2

!md5sum sample.sbet
196c21f16f07ceae180888b12e9edc56  sample.sbet

!md5sum 2010_202_S220_subsampled.sbet
e8f7283deb887e16b05b08581bd7d2bb  2010_202_S220_subsampled.sbet

!md5sum 2011_194_S250A_Stbd_subsampled.sbet
72e5bab716485b53ecde9aa1cfc90719  2011_194_S250A_Stbd_subsampled.sbet

To remove a bookmark, do 

bookmark -d c24

To get rid of all bookmarks: 

bookmark -r

Creating a bash alias for mercurial updating the class

Getting the lastest version of the class notes by hand in bash looks like this: 

researchtools@ubuntu:~$ cd ~/projects/researchtools/

researchtools@ubuntu:~/projects/researchtools$ hg pull

warning: bitbucket.org certificate with fingerprint 81:2b:08:90:dc:d3:71:ee:e0:7c:b4:75:ce:9b:6c:48:94:56:a1:fe not verified (check hostfingerprints or web.cacerts config setting)
pulling from https://bitbucket.org/schwehr/researchtools
warning: bitbucket.org certificate with fingerprint 81:2b:08:90:dc:d3:71:ee:e0:7c:b4:75:ce:9b:6c:48:94:56:a1:fe not verified (check hostfingerprints or web.cacerts config setting)
searching for changes
# -- snip --
warning: bitbucket.org certificate with fingerprint 81:2b:08:90:dc:d3:71:ee:e0:7c:b4:75:ce:9b:6c:48:94:56:a1:fe not verified (check hostfingerprints or web.cacerts config setting)
adding changesets
adding manifests
adding file changes
added 4 changesets with 7 changes to 5 files
(run 'hg update' to get a working copy)

researchtools@ubuntu:~/projects/researchtools$ hg update
merging class/23-python-binary-files-part-3.org
4 files updated, 1 files merged, 0 files removed, 0 files unresolved

That's not hard, but we want to make this trivial. Edit your ~/.bashaliases file. Add this line: 

# Specific to the research tools class
alias rtupdate='(cd ~/projects/researchtools; hg pull; hg update)'

The parentheses "()" around the command create a "scope" in which the cd command lives. When bash gets to the right hand ")" is will back out of the researchtools directory and leave you where you started.

These aliases are not active until you create a new terminal or source the alias file in an existing terminal. 

alias rtupdate # try to list the alias
# bash: alias: rtupdate: not found
source ~/.bash_aliases
alias rtupdate
# your new alias should show up

# To list all aliases:
alias

Where were we last time? 

#!/usr/bin/env python

'''Decode Applanix POSPac SBET IMU binary files'''

import struct
import math
# Use the pprint function from the pprint module
from pprint import pprint

field_names = ('time', 'latitude', 'longitude', 'altitude', \
          'x_vel', 'y_vel', 'z_vel', \
          'roll', 'pitch', 'platform_heading', 'wander_angle', \
          'x_acceleration', 'y_acceleration', 'z_acceleration', \
          'x_angular_rate', 'y_angular_rate', 'z_angular')

datagram_size = 136 # 8*17 bytes per datagram

def num_datagrams(data):
    'How many packets are in data'

    assert( len(data) % datagram_size == 0 )

    return len(data) / datagram_size

def get_offset(datagram_number):
    'Calculate the starting offset of a datagram.  First datagram is number 0'
    return datagram_number * datagram_size

def decode(data, offset=0):
    'Decipher a SBET datagram from binary'
    values = struct.unpack('17d',data[ offset + 0 : offset + 8*17])

    sbet_values = dict(zip (field_names, values))

    sbet_values['lat_deg'] = math.degrees(sbet_values['latitude'])
    sbet_values['lon_deg'] = math.degrees(sbet_values['longitude'])

    return sbet_values

def load_sbet_file(filename):
    '''This is a GENERATOR that we can loop over with a for'''
    sbet_file = open(filename)
    sbet_data = sbet_file.read()

    for datagram_index in range( num_datagrams(sbet_data) ):
        offset = get_offset(datagram_index)
        datagram = decode(sbet_data, offset)
        datagram['index'] = datagram_index
        yield datagram

def main():
    print 'Starting main'
    sbet_file = open('sample.sbet')
    sbet_data = sbet_file.read()

    print 'Number of datagrams:', num_datagrams(sbet_data)

    print 'Datagram Number, Time, x, y'

    for datagram_index in range( num_datagrams(sbet_data) ):
        offset = get_offset(datagram_index)
        datagram = decode(sbet_data, offset)

        print datagram_index, datagram['time'], datagram['lon_deg'], datagram['lat_deg']

if __name__ == '__main__':
    print 'starting to run script...'
    main()
    print 'script done!'

Command line arguments    commandlineargs

TODO fileinput

If we were not working with binary files, we might try the fileinput module. However, I'll have to leave that for another time.

searching for files with glob    glob

If we know something about the names of the files we want to work with, we can use glob. Glob gives us bash command line like file name expansion with "*", "?", and "[0-9]" style expansion. Try it from inside of ipython: 

import glob
glob.glob('*.py')
glob.glob('*.sbet')

Now change your main to handle all of the sbet files in the current directory. This is not a good way to handle files, but it can be useful.

Indent code in main with C-c >, change the loadsbetfile to take a filename argument and add the for loop.

Remove the open, read, and print of the number of datagrams lines.

You main function should look like this: 

def main():
    print 'Starting main'

    import glob

    for filename in glob.glob('*.sbet'):
        print '====',filename,'===='
        print 'Datagram Number, Time, x, y'

        for datagram_index, datagram in enumerate(load_sbet_file(filename)):
            if datagram_index % 10 == 0:
                print datagram_index, datagram['time'], datagram['lon_deg'], datagram['lat_deg']

Now run it from ipython: 

run sbet

Simple route with sys.argv    sys

Bet yet, the person using the sbet.py program should be able to specify which sbet files she wants to use. We can do this by using sys.argv. Check out argv from ipython: 

import sys
print sys.argv

# any file names specified will be after the 1st parameter, which
# is the name of the program.

print sys.argv[1:]

Remove the glob code from your main and replace it to use sys.argv. Your code should look like this: 

def main():
    print 'Starting main'

    import sys

    for filename in sys.argv[1:]:
        print '====',filename,'===='
        print 'Datagram Number, Time, x, y'

        for datagram_index, datagram in enumerate(load_sbet_file(filename)):
            if datagram_index % 10 == 0:
                print datagram_index, datagram['time'], datagram['lon_deg'], datagram['lat_deg']

It would be nice if shell expansion of "glob" style worked, but for ipython 0.10.2, we have to list out all the file names

http://stackoverflow.com/questions/8227705/run-from-ipython-with-glob-style-expansion 

filenames
run sbet.py sample.sbet 2010_202_S220_subsampled.sbet 2011_194_S250A_Stbd_subsampled.sbet

Your results should look like this: 

starting to run script...
Starting main
==== sample.sbet ====
Datagram Number, Time, x, y
0 334959.004823 -146.675232704 60.4443123064
10 335458.991726 -146.631176844 60.4833850599
20 335958.978642 -146.615374641 60.488061874
30 336458.965552 -146.610408727 60.4884544574
40 336958.952453 -146.602068248 60.4880620038
50 337458.939347 -146.601381986 60.4873117644
60 337958.926239 -146.614299722 60.488558233
70 338458.913138 -146.631671861 60.4823912283
80 338958.900046 -146.6171884 60.4849670034
90 339458.886961 -146.638808522 60.4798499224
100 339958.873884 -146.641052374 60.4777459053
110 340458.860796 -146.640432902 60.4794631211
120 340958.847702 -146.639497417 60.4777739654
130 341458.834603 -146.64539724 60.4721610761
140 341958.821503 -146.63946463 60.4730424798
150 342458.808406 -146.65277304 60.467285398
160 342958.795311 -146.669429917 60.4556509106
==== 2010_202_S220_subsampled.sbet ====
Datagram Number, Time, x, y
0 309498.001641 -168.105985062 65.5652441157
10 310497.990568 -168.14460618 65.576237069
20 311497.979504 -168.217203577 65.5765027734
30 312497.968453 -168.286847083 65.5766343791
40 313497.957407 -168.360572515 65.5768083537
50 314497.946366 -168.430597117 65.5767847792
60 315497.935336 -168.502290483 65.5768396777
70 316497.924312 -168.562203526 65.5784574745
==== 2011_194_S250A_Stbd_subsampled.sbet ====
Datagram Number, Time, x, y
0 273498.006144 -75.6779674319 36.9993413966
10 274498.035903 -75.6686272625 37.0166578669
20 275498.065662 -75.6303574293 37.0128677637
30 276498.09543 -75.5838353852 37.0129553714
40 277498.125213 -75.5375106226 37.013026657
50 278498.155027 -75.5016787502 37.0139588907
60 279498.184882 -75.544032377 37.0140028866
70 280498.214787 -75.5869761469 37.0139670547
80 281498.244734 -75.6296578787 37.0137003076
90 282498.274713 -75.6712520852 37.0123495064
100 283498.304712 -75.6345773566 37.0144177023
110 284498.33472 -75.5934162586 37.0146980809
120 285498.364735 -75.552605247 37.0144545719
130 286498.394766 -75.5115917803 37.0146829522
140 287498.424822 -75.5230051401 37.0154931321
150 288498.454905 -75.5635060081 37.0154547408
160 289498.485012 -75.6045727647 37.0156019109
170 290498.515137 -75.645795915 37.0153942394
180 291498.545265 -75.6613422226 37.0160430919
190 292498.575392 -75.6248025467 37.0159742854
200 293498.605513 -75.5837033162 37.0163109221
210 294498.63563 -75.5420885061 37.0157435582
220 295498.665747 -75.5011903989 37.0152076818
230 296498.695871 -75.5359292325 37.0165480198
240 297498.726 -75.576711627 37.0167642931
250 298498.756139 -75.6165338265 37.0169717959
260 299498.786282 -75.6577022044 37.0168299723
270 0.0 0.0 0.0
280 0.0 0.0 0.0
290 0.0 0.0 0.0
300 0.0 0.0 0.0
310 0.0 0.0 0.0
320 0.0 0.0 0.0
330 0.0 0.0 0.0
340 0.0 0.0 0.0
350 0.0 0.0 0.0
360 0.0 0.0 0.0
370 0.0 0.0 0.0
380 0.0 0.0 0.0
390 0.0 0.0 0.0
400 0.0 0.0 0.0
410 0.0 0.0 0.0
420 0.0 0.0 0.0
430 0.0 0.0 0.0
440 0.0 0.0 0.0
450 0.0 0.0 0.0
460 0.0 0.0 0.0
470 0.0 0.0 0.0
480 0.0 0.0 0.0
490 0.0 0.0 0.0
500 0.0 0.0 0.0
510 0.0 0.0 0.0
520 299498.786282 -75.6577022044 37.0168299723
530 299998.801354 -75.6780952432 37.0165026156
script done!

Uh oh! Zeros!

More flexible arguments

Please do NOT write your own command line option parse. Also, please don't use the older "optparse". If you use argparse, other people will be better able to work with your code.

http://www.doughellmann.com/PyMOTW/argparse/

Change your main to look like this: 

def main():
    print 'Starting main'

    import sys, argparse

    parser = argparse.ArgumentParser(description='Parse SBET files')
    parser.add_argument('filenames', type=str, nargs='+', help='SBET files')
    args = parser.parse_args() # uses sys.argv

    for filename in args.filenames:
        print '====',filename,'===='
        print 'Datagram Number, Time, x, y'

        for datagram_index, datagram in enumerate(load_sbet_file(filename)):
            if datagram_index % 10 == 0:
                print datagram_index, datagram['time'], datagram['lon_deg'], datagram['lat_deg']

Now try running it from ipython: 

run sbet.py --help
run sbet.py sample.sbet 2010_202_S220_subsampled.sbet 2011_194_S250A_Stbd_subsampled.sbet

We do not need any options right now, but this is a much better way to handle command line arguments.

It is time to write out kml files    kml

Inside of main, we need to create the kml: 

    for filename in args.filenames:
        out = open(filename+'.kml','w')
        out.write('''<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://www.opengis.net/kml/2.2">
    <Document>
            <Placemark>
                    <name>{filename}</name>
                    <LineString>
                            <coordinates>
        '''.format(filename=filename) )

        for datagram_index, datagram in enumerate(load_sbet_file(filename)):
            if datagram_index % 10 == 0:
                print datagram_index, datagram['time'], datagram['lon_deg'], datagram['lat_deg']
            out.write('{x},{y}\n'.format(x=datagram['lon_deg'], y=datagram['lat_deg']))

        out.write('''\t\t\t\t</coordinates>
\t\t\t</LineString>
\t\t</Placemark>
\t</Document>
</kml>
        ''')

Histories

history from ipython 

In [92]: history 1 92
1 : _ip.magic("cd class")
2 : _ip.system("ls -F ")
3 : _ip.system("ls -F -l")
4 : _ip.magic("pwd ")
5 : _ip.magic("cd researchtools/class/")
6 : _ip.magic("pwd ")
7 : _ip.system("hg pull")
8 : _ip.system("hg update")
9 : _ip.system("ls -F -l > ~/after.txt")
11: _ip.system("diff  --unified ~/before.txt ~/after.txt")
12: _ip.system("mkdir ~/class/24")
14: _ip.magic("cd ~/class/24")
15: _ip.magic("bookmark c24")
16: _ip.magic("bookmark -l")
17: _ip.magic("pwd ")
18: _ip.magic("cd hgclass")
19: _ip.magic("pwd ")
20: _ip.magic("bookmark -l")
21: _ip.magic("cd c24")
22: _ip.magic("cd hgclass")
23: _ip.magic("cd class")
24: _ip.magic("pwd ")
25: _ip.magic("bookmark hgclass")
26: _ip.magic("bookmark -l")
27: _ip.magic("cd c24")
28: _ip.magic("pwd ")
29: _ip.magic("logstart -o -r log-class-24.py")
30: _ip.system("ls -F ")
31: _ip.system("less log-class-24.py")
32: _ip.magic("dhist ")
34: _ip.magic("cd -2")
35: _ip.magic("cd -1")
36: _dh
37: _dh[1]
38: _ip.magic("alias ")
39: _ip.magic("alias rtupdate (cd /home/researchtools/projects/researchtools/; hg pull; hg update)")
40: _ip.system("(cd /home/researchtools/projects/researchtools/; hg pull; hg update) ")
41: _ip.magic("pwd ")
42: _ip.magic("cd c24")
43: _ip.magic("alias ")
45: _ip.magic("store rtupdate")
46: _ip.system("curl -O http://vislab-ccom.unh.edu/~schwehr/Classes/2011/esci895-researchtools/examples/21/sample.sbet.bz2")
47: _ip.system("curl -O http://vislab-ccom.unh.edu/~schwehr/Classes/2011/esci895-researchtools/examples/24/2010_202_S220_subsampled.sbet.bz2")
48: _ip.system("curl -O http://vislab-ccom.unh.edu/~schwehr/Classes/2011/esci895-researchtools/examples/24/2011_194_S250A_Stbd_subsampled.sbet.bz2")
50: _ip.system("ls -F -l")
51: _ip.system("bunzip2 sample.sbet.bz2")
52: _ip.system("bunzip2 2010_202_S220_subsampled.sbet.bz2")
53: _ip.system("bunzip2 2011_194_S250A_Stbd_subsampled.sbet.bz2")
54: _ip.system("ls -F -l")
55: _ip.magic("run sbet.py")
56: import glob
57: glob.glob('*.py')
58: glob.glob('*.sbet')
59: _ip.system("ls -F ")
60: glob.glob('2010*')
62: _ip.magic("run sbet.py")
63: import sys
64: sys.argv
65: print sys.argv
66: print sys.argv[1:]
68: _ip.magic("run sbet.py sample.sbet")
69: _ip.system("ls -F ")
70: _ip.magic("run sbet.py sample.sbet 2010_202_S220_subsampled.sbet")
71: import argparse
72: parser = argparse.ArgumentParser(description='Parse SBET files')
73: args = parser.parse_args()
74: args
75: parser.parse_args(['--help',] )
76: _ip.magic("run sbet.py --help")
77: _ip.magic("run sbet.py")
80: _ip.magic("run sbet.py sample.sbet")
82: _ip.magic("run sbet.py sample.sbet 2011_194_S250A_Stbd_subsampled.sbet")
86: _ip.magic("pwd ")
87: _ip.magic("run sbet.py sample.sbet 2010_202_S220_subsampled.sbet 2011_194_S250A_Stbd_subsampled.sbet")
88: _ip.system("ls -F -l")
89: _ip.system("less 2011_194_S250A_Stbd_subsampled.sbet.kml")
90: import sys
91: sys.float_info.epsilon

ipython log 

cd class
ls
ls -l
pwd
#[Out]# '/home/researchtools/projects'
cd researchtools/class/
pwd
#[Out]# '/home/researchtools/projects/researchtools/class'
!hg pull
!hg update
ls -l > ~/after.txt
!diff  --unified ~/before.txt ~/after.txt
mkdir ~/class/24
cd ~/class/24
bookmark c24
bookmark -l
pwd
#[Out]# '/home/researchtools/class/24'
cd hgclass
pwd
#[Out]# '/home/researchtools/projects/researchtools'
bookmark -l
cd c24
cd hgclass
cd class
pwd
#[Out]# '/home/researchtools/projects/researchtools/class'
bookmark hgclass
bookmark -l
cd c24
pwd
#[Out]# '/home/researchtools/class/24'
ls
less log-class-24.py
dhist
cd -2
cd -1
_dh
_dh[1]
#[Out]# '/home/researchtools/class/10'
alias
alias rtupdate (cd /home/researchtools/projects/researchtools/; hg pull; hg update)
rtupdate
pwd
#[Out]# '/home/researchtools/class/10'
cd c24
alias 
store rtupdate
!curl -O http://vislab-ccom.unh.edu/~schwehr/Classes/2011/esci895-researchtools/examples/21/sample.sbet.bz2
!curl -O http://vislab-ccom.unh.edu/~schwehr/Classes/2011/esci895-researchtools/examples/24/2010_202_S220_subsampled.sbet.bz2
!curl -O http://vislab-ccom.unh.edu/~schwehr/Classes/2011/esci895-researchtools/examples/24/2011_194_S250A_Stbd_subsampled.sbet.bz2
ls -l
!bunzip2 sample.sbet.bz2
!bunzip2 2010_202_S220_subsampled.sbet.bz2
!bunzip2 2011_194_S250A_Stbd_subsampled.sbet.bz2
ls -l
run sbet.py
import glob
glob.glob('*.py')
#[Out]# ['log-class-24.py', 'sbet.py']
glob.glob('*.sbet')
#[Out]# ['2010_202_S220_subsampled.sbet', 'sample.sbet', '2011_194_S250A_Stbd_subsampled.sbet']
ls
glob.glob('2010*')
#[Out]# ['2010_202_S220_subsampled.sbet']
run sbet.py
import sys
sys.argv
#[Out]# ['/usr/bin/ipython']
print sys.argv
print sys.argv[1:]
run sbet.py sample.sbet
ls
run sbet.py sample.sbet 2010_202_S220_subsampled.sbet
import argparse
parser = argparse.ArgumentParser(description='Parse SBET files')
args = parser.parse_args()
args
#[Out]# Namespace()
parser.parse_args(['--help',] )
run sbet.py --help
run sbet.py
run sbet.py sample.sbet
run sbet.py sample.sbet 2011_194_S250A_Stbd_subsampled.sbet
run sbet.py sample.sbet 2011_194_S250A_Stbd_subsampled.sbet
pwd
#[Out]# '/home/researchtools/class/24'
run sbet.py sample.sbet 2010_202_S220_subsampled.sbet 2011_194_S250A_Stbd_subsampled.sbet
ls -l
less 2011_194_S250A_Stbd_subsampled.sbet.kml
import sys
sys.float_info.epsilon
#[Out]# 2.220446049250313e-16
history 1 92

bash history 

2000  ipython
2001  cd projects/researchtools/class/
2002  ls
2003  mv 24-python-binary-files-part-4.org{,.old}
2004  ls
2005  fg
2006  cd ../..
2007  rm -rf researchtools/
2008  hg clone https://bitbucket.org/schwehr/researchtools
2009  ipython
2010  cd ~/class/24
2011  ls -l
2012  chmod +x sbet.py
2013  ls -l *.py
2014  ./sbet.py --help
2015  ./sbet.py sample.sbet 
2016  ./sbet.py *.sbet
2017  fg
2018  history

final source 

#!/usr/bin/env python

'''Decode Applanix POSPac SBET IMU binary files'''

import struct
import math
# Use the pprint function from the pprint module
from pprint import pprint

field_names = ('time', 'latitude', 'longitude', 'altitude', \
          'x_vel', 'y_vel', 'z_vel', \
          'roll', 'pitch', 'platform_heading', 'wander_angle', \
          'x_acceleration', 'y_acceleration', 'z_acceleration', \
          'x_angular_rate', 'y_angular_rate', 'z_angular')

datagram_size = 136 # 8*17 bytes per datagram

def num_datagrams(data):
    'How many packets are in data'

    assert( len(data) % datagram_size == 0 )

    return len(data) / datagram_size

def get_offset(datagram_number):
    'Calculate the starting offset of a datagram.  First datagram is number 0'
    return datagram_number * datagram_size

def decode(data, offset=0):
    'Decipher a SBET datagram from binary'
    values = struct.unpack('17d',data[ offset + 0 : offset + 8*17])

    sbet_values = dict(zip (field_names, values))

    sbet_values['lat_deg'] = math.degrees(sbet_values['latitude'])
    sbet_values['lon_deg'] = math.degrees(sbet_values['longitude'])

    return sbet_values

def load_sbet_file(filename):
    '''This is a GENERATOR that we can loop over with a for'''
    sbet_file = open(filename)
    sbet_data = sbet_file.read()

    for datagram_index in range( num_datagrams(sbet_data) ):
        offset = get_offset(datagram_index)
        datagram = decode(sbet_data, offset)
        datagram['index'] = datagram_index
        yield datagram

def main():
    import glob
    import sys

    print 'Starting main'

    import sys, argparse

    parser = argparse.ArgumentParser(description='Parse SBET files')
    parser.add_argument('filenames', type=str, nargs='+', help='SBET files')
    args = parser.parse_args() # uses sys.argv

    print 'filenames:', args.filenames

    for filename in args.filenames:
        print '====',filename,'===='
        out = open(filename+'.kml', 'w')
        out.write('''<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://www.opengis.net/kml/2.2">
    <Document>
            <Placemark>
                    <name>{filename}</name>
                    <LineString>
                            <coordinates>
        '''.format(filename=filename) )

        print 'Datagram Number, Time, x, y'
        for datagram_index, datagram in enumerate(load_sbet_file( filename )):
            if datagram_index % 20 == 0:
                print datagram_index, datagram['time'], datagram['lon_deg'], datagram['lat_deg']
            out.write('{x},{y}\n'.format(x=datagram['lon_deg'], y=datagram['lat_deg']))

        out.write('''\t\t\t\t</coordinates>
\t\t\t</LineString>
\t\t</Placemark>
\t</Document>
</kml>
        ''')

if __name__ == '__main__':
    print 'starting to run script...'
    main()
    print 'script done!'

Author: Kurt Schwehr

Date: <2011-11-22 Tue>

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