Implement a dialog to plot and export GPS data

Create a dialog with buttons to plot and export GPS data.

Show information about a GPS data point when user clicks on it.

#19 (closed)

sohstationviewer/model/mseed/mseed.py

 """
 MSeed object to hold and process MSeed data
 """
-
+import functools
+import operator
 import os
 from pathlib import Path
 from typing import Dict, Tuple, List, Set
@@ -11,6 +12,7 @@ from obspy.core import Stream
 from sohstationviewer.conf import constants
 from sohstationviewer.controller.util import validateFile
 from sohstationviewer.model.data_type_model import DataTypeModel, ThreadStopped
+from sohstationviewer.model.gps_point import GPSPoint
 from sohstationviewer.model.handling_data import (
     readWaveformMSeed, squash_gaps, checkWFChan, sortData, readSOHTrace,
 )
@@ -56,6 +58,8 @@ class MSeed(DataTypeModel):
         if len(self.reqWFChans) != 0:
             self.readWFFiles(self.selectedKey)
 
+        self.get_gps_data_q330()
+
     def read_soh_and_index_waveform(self, folder: str):
         """
             + read waveform data for filename associate with time range
@@ -309,3 +313,121 @@ class MSeed(DataTypeModel):
                         f'Read {count} waveform files', LogType.INFO)
 
         sortData(self.waveformData)
+
+    def get_gps_data_q330(self):
+        """
+        Read LOG channel and extract GPS data stored in Q330 data set.
+        """
+        for station in self.logData:
+            if station == 'TEXT':
+                continue
+            # Q330 log data is composed of a list of string, so we combine them
+            # into one big string for ease of processing.
+            log_str = functools.reduce(
+                operator.iconcat, self.logData[station]['LOG'], ''
+            )
+
+            log_lines = [line for line in log_str.splitlines() if line != '']
+            for idx, line in enumerate(log_lines):
+                if line == "GPS Status":
+                    # We are assuming that a GPS status report is 12 lines
+                    # long, has a specific format, and is followed by a PLL
+                    # status report. This method call checks if these
+                    # preconditions hold and raise an error if not.
+                    self.check_gps_status_format_q330(log_lines[idx:idx + 13])
+
+                    point = self.extract_gps_point_q330(
+                        log_lines[idx:idx + 12]
+                    )
+                    self.gps_points.append(point)
+
+    @staticmethod
+    def extract_gps_point_q330(gps_status_lines: List[str]) -> GPSPoint:
+        # Last timemark and fix type are always available, so we have to get
+        # them before doing anything else.
+        last_timemark = gps_status_lines[11][19:]
+        fix_type = gps_status_lines[3][10:]
+
+        # If location data is missing, we set them to 0.
+        if gps_status_lines[5] == 'Latitude: ':
+            return GPSPoint(last_timemark, fix_type, 0, 0, 0, 0, '')
+
+        num_sats_used = int(gps_status_lines[8].split(': ')[1])
+
+        # Height is encoded as a float followed by the unit. We
+        # don't know how many characters the unit is composed of,
+        # so we have to loop through the height string backward
+        # until we can detect the end of the height value.
+        height_str: str = gps_status_lines[4].split(': ')[1]
+        # Start pass the end of the string and look backward one
+        # index every iteration so we don't have to add 1 to the
+        # final index.
+        i = len(height_str)
+        current_char = height_str[i - 1]
+        while current_char != '.' and not current_char.isnumeric():
+            i -= 1
+            current_char = height_str[i - 1]
+        height = float(height_str[:i])
+        height_unit = height_str[i:]
+
+        # Latitude and longitude are encoded in the format
+        # <degree><decimal minute><cardinal direction>. For
+        # latitude, <degree> has two characters, while for longitude, <degree>
+        # has three.
+        # To make the GPS points easier to plot, we convert the latitude and
+        # longitude to decimal degree.
+        raw_latitude = gps_status_lines[5].split(': ')[1]
+        lat_degree = int(raw_latitude[:2])
+        lat_minute = float(raw_latitude[2:-1]) / 60
+        latitude = lat_degree + lat_minute
+        if raw_latitude[-1].lower() == 's':
+            latitude = -latitude
+
+        raw_longitude = gps_status_lines[6].split(': ')[1]
+        long_degree = int(raw_longitude[:3])
+        long_minute = float(raw_longitude[3:-1]) / 60
+        longitude = long_degree + long_minute
+        if raw_longitude[-1].lower() == 'w':
+            longitude = -longitude
+
+        gps_point = GPSPoint(last_timemark, fix_type, num_sats_used,
+                             latitude, longitude, height, height_unit)
+        return gps_point
+
+    @staticmethod
+    def check_gps_status_format_q330(gps_status_lines: List[str]):
+        if gps_status_lines[12].lower() != 'pll status':
+            raise ValueError(
+                'Q330 log data is malformed. '
+                'PLL status does not follow GPS status.'
+            )
+        if 'fix type' not in gps_status_lines[3].lower():
+            raise ValueError(
+                'Q330 log data is malformed. '
+                'Fix type is not at expected position.'
+            )
+        if 'height' not in gps_status_lines[4].lower():
+            raise ValueError(
+                'Q330 log data is malformed. '
+                'Height is not at expected position.'
+            )
+        if 'latitude' not in gps_status_lines[5].lower():
+            raise ValueError(
+                'Q330 log data is malformed. '
+                'Latitude is not at expected position.'
+            )
+        if 'longitude' not in gps_status_lines[6].lower():
+            raise ValueError(
+                'Q330 log data is malformed. '
+                'Longitude is not at expected position.'
+            )
+        if 'sat. used' not in gps_status_lines[8].lower():
+            raise ValueError(
+                'Q330 log data is malformed. '
+                'Sat. Used is not at expected position.'
+            )
+        if 'last gps timemark' not in gps_status_lines[11].lower():
+            raise ValueError(
+                'Q330 log data is malformed. '
+                'Last GPS timemark is not at expected position.'
+            )