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feat: extract_mcap — /navigation/altitude (Kogger) -> HDF5 altitude_m + seafloor_depth_m

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Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
This commit is contained in:
Floppyrj45
2026-04-24 11:48:46 +02:00
parent ac7b89bed5
commit 7330b230b8
2 changed files with 60 additions and 3 deletions
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25
extract/extract_mcap.py
View File

@@ -7,13 +7,15 @@ from mcap_ros2.reader import read_ros2_messages
TOPIC_GPS = "/mavros/global_position/global" # sensor_msgs/NavSatFix
TOPIC_DEPTH = "/mavros/global_position/rel_alt" # std_msgs/Float64
TOPIC_ALT = "/navigation/altitude" # std_msgs/Float64 - altitude above seafloor
def write_auv_mcap_group(h5_path: str,
t_ns: np.ndarray,
lat: np.ndarray,
lon: np.ndarray,
depth_m: np.ndarray) -> None:
depth_m: np.ndarray,
altitude_m: np.ndarray | None = None) -> None:
with h5py.File(h5_path, "a") as f:
if "auv_mcap" in f:
del f["auv_mcap"]
@@ -22,6 +24,9 @@ def write_auv_mcap_group(h5_path: str,
grp.create_dataset("lat", data=lat.astype(np.float64), compression="gzip")
grp.create_dataset("lon", data=lon.astype(np.float64), compression="gzip")
grp.create_dataset("depth_m", data=depth_m.astype(np.float64), compression="gzip")
if altitude_m is not None:
grp.create_dataset("altitude_m", data=altitude_m.astype(np.float64), compression="gzip")
grp.create_dataset("seafloor_depth_m", data=(depth_m + altitude_m).astype(np.float64), compression="gzip")
def _iter_topic(bag_dir: str, topic: str):
@@ -60,8 +65,22 @@ def extract(bag_dir: str, out_h5: str) -> None:
ts_arr = np.array(ts, dtype=np.int64)
depths = np.interp(ts_arr, depth_times_arr, depth_vals)
write_auv_mcap_group(out_h5, ts_arr, np.array(lats), np.array(lons), depths)
print(f"AUV MCAP: {len(ts)} fixes -> {out_h5} [/auv_mcap]")
alt_by_t: dict[int, float] = {}
for msg in _iter_topic(bag_dir, TOPIC_ALT):
alt_by_t[msg.log_time_ns] = float(msg.ros_msg.data)
if alt_by_t:
alt_times = sorted(alt_by_t.keys())
alt_vals = np.array([alt_by_t[k] for k in alt_times], dtype=np.float64)
alt_times_arr = np.array(alt_times, dtype=np.int64)
altitudes = np.interp(ts_arr, alt_times_arr, alt_vals)
else:
altitudes = None
print("WARNING: /navigation/altitude not found in bags", file=sys.stderr)
write_auv_mcap_group(out_h5, ts_arr, np.array(lats), np.array(lons), depths, altitudes)
alt_status = "ok" if altitudes is not None else "missing"
print(f"AUV MCAP: {len(ts)} fixes, depth ok, altitude {alt_status} -> {out_h5} [/auv_mcap]")
if __name__ == "__main__":

38
tests/test_extract_mcap.py
View File

@@ -22,3 +22,41 @@ def test_write_auv_mcap_group():
assert list(f["auv_mcap/t_ns"][:]) == list(t)
finally:
os.unlink(path)
def test_write_auv_mcap_group_with_altitude():
from extract.extract_mcap import write_auv_mcap_group
t = np.array([1000, 2000, 3000], dtype=np.int64)
lat = np.array([43.1, 43.2, 43.3])
lon = np.array([5.6, 5.61, 5.62])
depth = np.array([5.0, 5.5, 6.0])
alt = np.array([1.2, 1.3, 1.1])
with tempfile.NamedTemporaryFile(suffix=".h5", delete=False) as tmp:
path = tmp.name
try:
write_auv_mcap_group(path, t, lat, lon, depth, alt)
with h5py.File(path, "r") as f:
assert "altitude_m" in f["auv_mcap"]
assert "seafloor_depth_m" in f["auv_mcap"]
assert np.allclose(f["auv_mcap/altitude_m"][:], alt)
assert np.allclose(f["auv_mcap/seafloor_depth_m"][:], depth + alt)
finally:
os.unlink(path)
def test_write_auv_mcap_group_without_altitude():
from extract.extract_mcap import write_auv_mcap_group
t = np.array([1000, 2000], dtype=np.int64)
lat = np.zeros(2)
lon = np.zeros(2)
depth = np.array([3.0, 4.0])
with tempfile.NamedTemporaryFile(suffix=".h5", delete=False) as tmp:
path = tmp.name
try:
write_auv_mcap_group(path, t, lat, lon, depth, altitude_m=None)
with h5py.File(path, "r") as f:
assert "altitude_m" not in f["auv_mcap"]
finally:
os.unlink(path)