Apply DelayScalar to get correct samples offset

equinor · Feb 27, 2023 · 3f692e8 · 3f692e8
1 parent 6107089
commit 3f692e8
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Showing 3 changed files with 10 additions and 1 deletion.
diff --git a/python/segyio/open.py b/python/segyio/open.py
@@ -172,8 +172,13 @@ def open(filename, mode="r", iline = 189,
     )
 
     try:
+        delay_scalar = f.header[0][segyio.TraceField.ScalarTraceHeader]
+        if delay_scalar == 0:
+            delay_scalar = 1
+        elif delay_scalar < 0:
+            delay_scalar = 1.0 / delay_scalar
         dt = segyio.tools.dt(f, fallback_dt = 4000.0) / 1000.0
-        t0 = f.header[0][segyio.TraceField.DelayRecordingTime]
+        t0 = f.header[0][segyio.TraceField.DelayRecordingTime] * abs(delay_scalar)
         samples = metrics['samplecount']
         f._samples = (numpy.arange(samples) * dt) + t0
 

diff --git a/python/test/segy.py b/python/test/segy.py
@@ -1968,3 +1968,7 @@ def test_groups_gather_equivalence():
 
         # group[(il, xl)] == gather[il, xl]
         npt.assert_array_equal(from_group, from_gather)
+
+def test_delay_scalar_applied():
+    with segyio.open(testdata / 'delay-scalar.sgy') as f:
+        assert f.samples[0] == 1000
diff --git a/test-data/delay-scalar.sgy b/test-data/delay-scalar.sgy