Add FlightTelemetryTools GPX and KML exporters.

Author: ztel42

FlightTelemetryTools/flight_telemetry/export_gpx.py

@@ -0,0 +1,74 @@
+"""GPX 1.1 track export."""
+
+from __future__ import annotations
+
+import xml.etree.ElementTree as ET
+from pathlib import Path
+from typing import List, Union
+from xml.dom import minidom
+
+from .models import TelemetryFrame
+
+PathLike = Union[str, Path]
+
+GPX_NS = "http://www.topografix.com/GPX/1/1"
+XSI_NS = "http://www.w3.org/2001/XMLSchema-instance"
+
+
+def _iso_time(frame: TelemetryFrame) -> str:
+    if frame.datetime_utc is not None:
+        return frame.datetime_utc.strftime("%Y-%m-%dT%H:%M:%S.%f")[:-3] + "Z"
+    # Fall back to cue start as offset from epoch-less video time — use a
+    # synthetic timeline anchored at 1970-01-01 so GPX always has <time>.
+    from datetime import datetime, timedelta, timezone
+
+    t = datetime(1970, 1, 1, tzinfo=timezone.utc) + timedelta(
+        milliseconds=frame.start_ms
+    )
+    return t.strftime("%Y-%m-%dT%H:%M:%S.%f")[:-3] + "Z"
+
+
+def frames_to_gpx(frames: List[TelemetryFrame], name: str = "DJI flight track") -> str:
+    """Build a GPX 1.1 document string with a single trk/trkseg."""
+    ET.register_namespace("", GPX_NS)
+    ET.register_namespace("xsi", XSI_NS)
+
+    gpx = ET.Element(
+        f"{{{GPX_NS}}}gpx",
+        {
+            "version": "1.1",
+            "creator": "FlightTelemetryTools",
+            f"{{{XSI_NS}}}schemaLocation": (
+                f"{GPX_NS} http://www.topografix.com/GPX/1/1/gpx.xsd"
+            ),
+        },
+    )
+    metadata = ET.SubElement(gpx, f"{{{GPX_NS}}}metadata")
+    ET.SubElement(metadata, f"{{{GPX_NS}}}name").text = name
+    ET.SubElement(metadata, f"{{{GPX_NS}}}desc").text = (
+        "Flight track exported from DJI SRT telemetry. "
+        "GPS from subtitles only; not a flight controller log."
+    )
+
+    trk = ET.SubElement(gpx, f"{{{GPX_NS}}}trk")
+    ET.SubElement(trk, f"{{{GPX_NS}}}name").text = name
+    seg = ET.SubElement(trk, f"{{{GPX_NS}}}trkseg")
+
+    for fr in frames:
+        pt = ET.SubElement(
+            seg,
+            f"{{{GPX_NS}}}trkpt",
+            {"lat": f"{fr.latitude:.7f}", "lon": f"{fr.longitude:.7f}"},
+        )
+        ET.SubElement(pt, f"{{{GPX_NS}}}ele").text = f"{fr.altitude_m:.3f}"
+        ET.SubElement(pt, f"{{{GPX_NS}}}time").text = _iso_time(fr)
+
+    rough = ET.tostring(gpx, encoding="utf-8")
+    parsed = minidom.parseString(rough)
+    return parsed.toprettyxml(indent="  ", encoding="utf-8").decode("utf-8")
+
+
+def write_gpx(frames: List[TelemetryFrame], path: PathLike, name: str = "DJI flight track") -> Path:
+    out = Path(path)
+    out.write_text(frames_to_gpx(frames, name=name), encoding="utf-8")
+    return out

FlightTelemetryTools/flight_telemetry/export_kml.py

@@ -0,0 +1,89 @@
+"""KML 2.2 LineString (+ gx:Track) export for Google Earth."""
+
+from __future__ import annotations
+
+import xml.etree.ElementTree as ET
+from pathlib import Path
+from typing import List, Union
+from xml.dom import minidom
+
+from .models import TelemetryFrame
+
+PathLike = Union[str, Path]
+
+KML_NS = "http://www.opengis.net/kml/2.2"
+GX_NS = "http://www.google.com/kml/ext/2.2"
+
+
+def _iso_time(frame: TelemetryFrame) -> str:
+    if frame.datetime_utc is not None:
+        return frame.datetime_utc.strftime("%Y-%m-%dT%H:%M:%S.%f")[:-3] + "Z"
+    from datetime import datetime, timedelta, timezone
+
+    t = datetime(1970, 1, 1, tzinfo=timezone.utc) + timedelta(
+        milliseconds=frame.start_ms
+    )
+    return t.strftime("%Y-%m-%dT%H:%M:%S.%f")[:-3] + "Z"
+
+
+def _altitude_mode(frames: List[TelemetryFrame]) -> str:
+    """Match altitudeMode to the dominant altitude source."""
+    if not frames:
+        return "absolute"
+    abs_n = sum(1 for f in frames if f.altitude_source == "absolute")
+    return "absolute" if abs_n >= len(frames) / 2 else "relativeToGround"
+
+
+def frames_to_kml(frames: List[TelemetryFrame], name: str = "DJI flight track") -> str:
+    """Build KML 2.2 with a LineString path and a gx:Track when times exist."""
+    ET.register_namespace("", KML_NS)
+    ET.register_namespace("gx", GX_NS)
+
+    kml = ET.Element(f"{{{KML_NS}}}kml")
+    doc = ET.SubElement(kml, f"{{{KML_NS}}}Document")
+    ET.SubElement(doc, f"{{{KML_NS}}}name").text = name
+    ET.SubElement(doc, f"{{{KML_NS}}}description").text = (
+        "Flight track exported from DJI SRT telemetry for Google Earth. "
+        "Coordinates and altitudes come from video subtitle metadata only; "
+        "this is not a flight-controller log. Speed may be recorded or "
+        "estimated from successive GPS points."
+    )
+
+    alt_mode = _altitude_mode(frames)
+
+    # LineString placemark (always)
+    pm = ET.SubElement(doc, f"{{{KML_NS}}}Placemark")
+    ET.SubElement(pm, f"{{{KML_NS}}}name").text = f"{name} (path)"
+    ET.SubElement(pm, f"{{{KML_NS}}}description").text = (
+        f"{len(frames)} points; altitudeMode={alt_mode}"
+    )
+    line = ET.SubElement(pm, f"{{{KML_NS}}}LineString")
+    ET.SubElement(line, f"{{{KML_NS}}}altitudeMode").text = alt_mode
+    ET.SubElement(line, f"{{{KML_NS}}}tessellate").text = "1"
+    coords = " ".join(
+        f"{f.longitude:.7f},{f.latitude:.7f},{f.altitude_m:.3f}" for f in frames
+    )
+    ET.SubElement(line, f"{{{KML_NS}}}coordinates").text = coords
+
+    # gx:Track with when/gx:coord
+    track_pm = ET.SubElement(doc, f"{{{KML_NS}}}Placemark")
+    ET.SubElement(track_pm, f"{{{KML_NS}}}name").text = f"{name} (track)"
+    track = ET.SubElement(track_pm, f"{{{GX_NS}}}Track")
+    ET.SubElement(track, f"{{{KML_NS}}}altitudeMode").text = alt_mode
+    for fr in frames:
+        ET.SubElement(track, f"{{{KML_NS}}}when").text = _iso_time(fr)
+    for fr in frames:
+        # gx:coord is lon lat alt (space-separated)
+        ET.SubElement(track, f"{{{GX_NS}}}coord").text = (
+            f"{fr.longitude:.7f} {fr.latitude:.7f} {fr.altitude_m:.3f}"
+        )
+
+    rough = ET.tostring(kml, encoding="utf-8")
+    parsed = minidom.parseString(rough)
+    return parsed.toprettyxml(indent="  ", encoding="utf-8").decode("utf-8")
+
+
+def write_kml(frames: List[TelemetryFrame], path: PathLike, name: str = "DJI flight track") -> Path:
+    out = Path(path)
+    out.write_text(frames_to_kml(frames, name=name), encoding="utf-8")
+    return out