EK60 Conversion: Drop channels that don't have power data (#1383)

* init commit

* simplify test

echopype/convert/set_groups_ek60.py

@@ -72,6 +72,13 @@ def __init__(self, *args, **kwargs):
         # In some examples the channels may not be ordered, thus sorting is required
         self.sorted_channel = dict(sorted(channel_ids.items(), key=lambda item: item[1]))
 
+        # Select channels where parser `power` is not empty
+        self.sorted_channel = {
+            key: value
+            for key, value in self.sorted_channel.items()
+            if len(self.parser_obj.ping_data_dict["power"][key]) != 0
+        }
+
         # obtain corresponding frequency dict from sorted channels
         self.freq = [
             self.parser_obj.config_datagram["transceivers"][ch]["frequency"]

echopype/tests/convert/test_convert_ek60.py

@@ -6,6 +6,7 @@
 import pytest
 
 from echopype import open_raw
+from echopype.convert import ParseEK60
 
 
 @pytest.fixture
@@ -236,3 +237,30 @@ def test_convert_ek60_different_num_channel_mode_values(file_path, ek60_path):
             ed["Sonar/Beam_group1"]["channel_mode"].data.dtype,
             np.float32
         )
+
+@pytest.mark.test
+@pytest.mark.integration
+def test_converting_ek60_raw_with_missing_channel_power():
+    """
+    Tests that we can convert a EK60 RAW file that has missing power data for a
+    specific channel.
+    """
+    # Parse RAW
+    raw_path = "echopype/test_data/ek60_missing_channel_power/Summer2017-D20170807-T171736.raw"
+    ek60_parser = ParseEK60(raw_path)
+    ek60_parser.parse_raw()
+
+    # Open RAW
+    ed = open_raw(raw_path, sonar_model="EK60")
+
+    # Get channels that have empty `power`
+    channels = list(ek60_parser.config_datagram["transceivers"].keys())
+    empty_power_chs = {
+        ch: ek60_parser.config_datagram["transceivers"][ch]["channel_id"]
+        for ch in channels
+        if len(ek60_parser.ping_data_dict["power"][ch]) == 0
+    } 
+
+    # Check that all empty power channels do not exist in the EchoData Beam group
+    for _, empty_power_channel_name in empty_power_chs.items():
+        assert empty_power_channel_name not in ed["Sonar/Beam_group1"]["channel"]