#! /usr/bin/python
# -*- coding: iso-8859-15 -*-
'''
========================================================================
Pre-processing navigation data files from RV "G.O. SARS".
Merge navigation and gravity data, using interpolation.

A time constant is provided - START_UNIX_TIME - and gravity records 
which are older will just be skipped. The reason is that gravity
records starts before the vessel left harbour, and navigation data 
are available when the ship left the shoreline (much later).

Survey:
	R/V "G.O. SARS"
	Period: 30 June 2008 - 17 July 2008
	P.I.: Prof. Dr. Rolf Birger Pedersen

Input:
	Two files:
		GRAV_FILE_NAME
		NAV_FILE_NAME
	from folder given by PATH (see declaration of these constants below).
	 
Output:
	File with name OUTFILE (constant, see below), in current directory

                  ###########################
                  ###    W-A-R-N-I-N-G    ###
                  ###########################
	
	Depth interpolation suffers from extensive sections of missing depth data 
	in navigation input data. Further processing of gravity data will possibly
	alter the metod of depth interpolation that is used here.

Documentation:
	http://www2.geo.uib.no/gravitymeter_wiki/index.php?n=Main.SARS2008

Version:
    -----------------------------------------------------
    Rev.  Date           By   Description
    -----------------------------------------------------
    0.1  13 March 2009   OM   Initial version


                University of Bergen
               Dept. of Earth Science
                    N o r w a y
=======================================================================
'''


from numarray import array,Float64
from cubicSpline import *


PATH         	=  "/home/olem/www/2008-SARS/navdata/"
GRAV_FILE_NAME	=  "gravdata-stage-1.txt"
NAV_FILE_NAME	=  "navdata-stage-1.txt"
OUTFILE			=  "gravdata-final.txt"
START_UNIX_TIME =  1214807736   # = first record in navdata file -> 30.06.2008,063536,70.457768333,17.148941667


NavTime_array	= []
Lat_array		= []
Lon_array		= []
Depth_array		= []
DepthTime_array = []


#---- First extract time, lat, lon and depth from nav data file, and place values into separate arrays
f = open(PATH + '/' + NAV_FILE_NAME)
for Line in f:
	s			= Line.strip().split(',')		# Explode after stripping off trailing <CR> in line
	UnixTime	= s[0]
	NavTime_array.append(int(UnixTime))
	Lat			= s[3]
	Lat_array.append(float(Lat))
	Lon			= s[4]
	Lon_array.append(float(Lon))
	Depth		= s[7]
	if (len(Depth) != 0) and (Depth != "0.00"):		# Skip empty depth field, or if it's zero
		Depth_array.append(float(Depth))
		DepthTime_array.append(int(UnixTime))
f.close()


#---- Next prepare interpolation on Time/Latatitude, Time/Longitude and Time/Depth data sets

xData		= array(NavTime_array, type='Float64')
xDepthData  = array(DepthTime_array, type='Float64')

yLatData	= array(Lat_array,  type='Float64')
kLat 		= curvatures(xData,yLatData)

yLonData 	= array(Lon_array,  type='Float64')
kLon 		= curvatures(xData,yLonData)

yDepthData 	= array(Depth_array,  type='Float64')
kDepth 		= curvatures(xDepthData,yDepthData)

#--- Prepare output file
g = open(OUTFILE, "w")
RecordsWritten = 0

#---- Then loop over all gravity records and calculate interpolated lat/lon/depth for each

f = open(PATH + '/' + GRAV_FILE_NAME)
for Line in f:
	s			= Line.strip().split(',')		# Explode after stripping off trailing <CR> in line
	UnixTime	= int(s[0])
	Date		= s[1]
	Time		= s[2]
	Gravity 	= s[3]
	
	if UnixTime >= START_UNIX_TIME:				# Skip records older then START_UNIX_TIME
		x 					= UnixTime
		Lat_Interpolated	= evalSpline(xData,yLatData,kLat,x)
		Lon_Interpolated	= evalSpline(xData,yLonData,kLon,x)
		Depth_Interpolated	= evalSpline(xDepthData,yDepthData,kDepth,x)
		if Depth_Interpolated <= 0.0:
			Depth_Interpolated = 0.0
		RecordsWritten	+=1
		g.write("%d,%s,%s,%1.9f,%1.9f,%1.1f,%s\n" % \
				(UnixTime, Date, Time, Lat_Interpolated, Lon_Interpolated, Depth_Interpolated, Gravity))
	
f.close()
g.close()


print "Done"
print "Wrote %d records to file: %s" % (RecordsWritten, OUTFILE)