Added Match class.

Works on Radiation so far, but fails on Position, because there is not attribute timestamp.
Going to write a wrapper class to be able to use same Match class on both of them.

functions.py

@@ -3,7 +3,7 @@
 
 ''' Classes used by main program. '''
 
-from datetime import datetime
+from datetime import datetime, timedelta
 import os
 import shutil
 from fractions import Fraction
@@ -90,6 +90,48 @@ class Photo:
         pic_aware_time = pic_naive_time.astimezone(local_timezone)
         return pic_aware_time
 
+class Match:
+    '''
+    Receives lists of time / radiation and GPS data and compares it to timestamp.
+    Then returns relevant values matching to time - or None
+
+    Arguments:
+    photo_time: timestamp of photo
+    radiation_list: list of timestamp / radiation values
+    position_list: list of timestamp / position / elevation values
+    
+    Returns:
+    timestamp: as datetime object
+    radiation: in µS/h as string
+    latitude: in decimal format as float
+    longitude: in decimal format as float
+    elevation: in meters as float
+    '''
+
+    def __init__(self, photo_time, radiation_list, position_list):
+#        self.radiation = self._find_match(photo_time, radiation_list)
+        self.position = self._find_match(photo_time, position_list)
+
+    def __repr__(self):
+        pass
+
+    def _find_match(self, photo_time, list):
+        valuelist = []
+        for row in list:
+            # Define timedelta and define timedelta datetime object.
+            delta = timedelta(seconds=60)
+            time_delta = abs(row.timestamp - photo_time)
+#            time_delta = abs(row[0] - photo_time)
+            # datetime objects should match with 1 minute precision.
+            if time_delta < delta:
+                element = (time_delta, row)
+                valuelist.append(element)
+        # Return the list item with the lowest timedelta in column 0.
+        # Column 2 contains the source objects untouched.
+        if valuelist:
+            return min(valuelist, key=lambda x: x[0])
+        return None
+
 class Exif:
     '''
     Converts, compiles and writes Exif-Tags from given arguemnts. 
@@ -103,8 +145,8 @@ class Exif:
     dry_run: whether to acutally write (True / False)
 
     Returns:
-    Latitude / Longitude in degrees
-    Exif-Comment that has been written (incl. radiation)
+    Latitude / Longitude: in degrees
+    Exif-Comment: that has been written (incl. radiation)
     '''
 
     def __init__(self, photo, dry_run, radiation, latitude, longitude, elevation):

rad_tag.py

@@ -10,7 +10,7 @@ import csv
 import argparse
 import pytz
 import gpxpy
-from functions import Radiation, Photo, Exif
+from functions import Radiation, Photo, Exif, Match
 
 # SIFACTOR for GQ Geiger counters
 
@@ -91,6 +91,8 @@ for src_photo in args.photos:
 
     # Here the matching magic has to happen
 
+    match = Match(photo.get_date, radiation_list, position_list)
+
     latitude = 51.0234024
     longitude = 7.248347
     radiation = 9001.15