Fix geometry detection in analyze_lines_for_guns to handle Type A cases correctly. Ensure all shot lines are processed and unique_guns_per_line is populated to prevent KeyError. Add tests for multiline Type A geometry scenarios.

Author: BrianMichell

src/mdio/segy/geometry.py

@@ -185,6 +185,10 @@ def analyze_lines_for_guns(
         num_guns = unique_guns_in_line.shape[0]
         unique_guns_per_line[str(line_val)] = list(unique_guns_in_line)
 
+        # Skip geometry detection if we already know it's Type A
+        if geom_type == ShotGunGeometryType.A:
+            continue
+
         for gun in unique_guns_in_line:
             gun_mask = gun_current == gun
             shots_for_gun = shot_current[gun_mask]
@@ -194,7 +198,7 @@ def analyze_lines_for_guns(
                 msg = "%s %s has %s shots; div by %s guns gives %s unique mod shots."
                 logger.info(msg, line_field, line_val, num_shots, num_guns, len(np.unique(mod_shots)))
                 geom_type = ShotGunGeometryType.A
-                return unique_lines, unique_guns_per_line, geom_type
+                break  # No need to check more guns for this line
 
     return unique_lines, unique_guns_per_line, geom_type
 
@@ -611,18 +615,29 @@ def transform(
             logger.info("%s: %s has guns: %s", line_field, line_val, guns)
             max_num_guns = max(len(guns), max_num_guns)
 
-        # Only calculate shot_index when shot points are interleaved across guns (Type B)
-        if geom_type == ShotGunGeometryType.B:
-            shot_index = np.empty(len(index_headers), dtype="uint32")
-            # Use .base if available (view of another array), otherwise use the array directly
-            base_array = index_headers.base if index_headers.base is not None else index_headers
-            index_headers = rfn.append_fields(base_array, "shot_index", shot_index)
+        # Always calculate shot_index - the OBN template requires it
+        shot_index = np.empty(len(index_headers), dtype="uint32")
+        # Use .base if available (view of another array), otherwise use the array directly
+        base_array = index_headers.base if index_headers.base is not None else index_headers
+        index_headers = rfn.append_fields(base_array, "shot_index", shot_index)
 
+        if geom_type == ShotGunGeometryType.B:
+            # Type B: shot points are interleaved across guns, divide to get dense index
             for line_val in unique_lines:
                 line_idxs = np.where(index_headers[line_field][:] == line_val)
                 index_headers["shot_index"][line_idxs] = np.floor(index_headers["shot_point"][line_idxs] / max_num_guns)
                 # Make shot index zero-based PER line
                 index_headers["shot_index"][line_idxs] -= index_headers["shot_index"][line_idxs].min()
+        else:
+            # Type A: shot points are already unique per gun, create 0-based index from unique values
+            for line_val in unique_lines:
+                line_idxs = np.where(index_headers[line_field][:] == line_val)[0]
+                shot_points = index_headers["shot_point"][line_idxs]
+                unique_shots = np.sort(np.unique(shot_points))
+                # Map each shot_point to its 0-based index
+                shot_to_idx = {sp: i for i, sp in enumerate(unique_shots)}
+                for i, idx in enumerate(line_idxs):
+                    index_headers["shot_index"][idx] = shot_to_idx[shot_points[i]]
 
         return index_headers
 

tests/integration/conftest.py

@@ -342,3 +342,43 @@ def segy_mock_obn_no_component(fake_segy_tmp: Path) -> Path:
         components=None,  # No component header
         filename_suffix="no_component",
     )
+
+
+@pytest.fixture(scope="module")
+def segy_mock_obn_multiline_type_a(fake_segy_tmp: Path) -> Path:
+    """Generate mock OBN SEG-Y file with multiple shot lines and Type A geometry.
+
+    This fixture tests the scenario where:
+    - Multiple shot lines exist (3 lines)
+    - Shot points are NOT interleaved across guns (Type A geometry)
+    - Each gun has the same dense shot point values
+
+    This specifically tests the fix for the bug where an early return in
+    analyze_lines_for_guns() would skip populating unique_guns_per_line for
+    lines after the first Type A detection, causing KeyError when later
+    code tried to access those lines.
+    """
+    num_samples = 25
+    receivers = [101, 102]
+    shot_lines = [1, 2, 3]  # Multiple lines to test all are processed
+    guns = [1, 2]
+    components = [1]  # Single component for simplicity
+
+    # Non-interleaved (Type A): both guns have the same shot point values
+    # This triggers Type A detection because floor(shot_point / num_guns)
+    # produces duplicates when shot points are dense per gun
+    shot_points_per_gun = {
+        1: [1, 2, 3],  # gun 1: dense shot points
+        2: [1, 2, 3],  # gun 2: same dense shot points (Type A)
+    }
+
+    return create_segy_mock_obn(
+        fake_segy_tmp,
+        num_samples=num_samples,
+        receivers=receivers,
+        shot_lines=shot_lines,
+        guns=guns,
+        shot_points_per_gun=shot_points_per_gun,
+        components=components,
+        filename_suffix="multiline_type_a",
+    )

tests/integration/test_import_obn_grid_overrides.py

@@ -158,3 +158,68 @@ def test_import_obn_without_calculate_shot_index_raises(
         error_message = str(exc_info.value)
         assert "shot_index" in error_message
         assert "ObnReceiverGathers3D" in error_message
+
+
+class TestImportObnMultilineTypeA:
+    """Test OBN SEG-Y import with multiple shot lines and Type A geometry.
+
+    This test class verifies the fix for a bug where analyze_lines_for_guns()
+    would return early upon detecting Type A geometry, leaving the
+    unique_guns_per_line dictionary incomplete. This caused KeyError when
+    CalculateShotIndex.transform() tried to access shot lines that weren't
+    in the dictionary.
+
+    Regression test for: KeyError when ingesting OBN data with multiple shot
+    lines where Type A geometry is detected on an earlier line.
+    """
+
+    def test_import_obn_multiline_type_a_all_lines_processed(
+        self,
+        segy_mock_obn_multiline_type_a: Path,
+        zarr_tmp: Path,
+    ) -> None:
+        """Test that all shot lines are processed with Type A geometry.
+
+        This test verifies that:
+        1. CalculateShotIndex works with Type A geometry (non-interleaved shots)
+        2. All shot lines are included in the output, not just the first one
+        3. shot_index is correctly calculated for Type A (0-based from unique values)
+        """
+        segy_spec = get_segy_mock_obn_spec(include_component=True)
+        grid_override = {"CalculateShotIndex": True}
+
+        segy_to_mdio(
+            segy_spec=segy_spec,
+            mdio_template=TemplateRegistry().get("ObnReceiverGathers3D"),
+            input_path=segy_mock_obn_multiline_type_a,
+            output_path=zarr_tmp,
+            overwrite=True,
+            grid_overrides=grid_override,
+        )
+
+        ds = open_mdio(zarr_tmp)
+
+        # Verify ALL shot lines are present (the bug would cause lines to be missing)
+        expected_shot_lines = [1, 2, 3]
+        xrt.assert_duckarray_equal(ds["shot_line"], expected_shot_lines)
+
+        # Verify guns are present
+        expected_guns = [1, 2]
+        xrt.assert_duckarray_equal(ds["gun"], expected_guns)
+
+        # Verify shot_index is calculated correctly for Type A geometry
+        # Type A: shot points [1, 2, 3] are already unique per gun
+        # shot_index should be 0-based indices: [0, 1, 2]
+        expected_shot_index = [0, 1, 2]
+        xrt.assert_duckarray_equal(ds["shot_index"], expected_shot_index)
+
+        # Verify other dimensions
+        expected_receivers = [101, 102]
+        xrt.assert_duckarray_equal(ds["receiver"], expected_receivers)
+
+        expected_components = [1]
+        xrt.assert_duckarray_equal(ds["component"], expected_components)
+
+        # Verify shot_point is preserved as a coordinate
+        assert "shot_point" in ds.coords
+        assert ds["shot_point"].dims == ("shot_line", "gun", "shot_index")