Calculate rough distance of high altitude balloon trip from WSPR data + generate KML

trip.py

#!/usr/bin/env python

# Calculate rough distance of the balloon trip from WSPR data
#
# Run `pip install maidenhead psycopg2-binary pyproj simplekml` for prereqs
#
# Simonas Kareiva <[email protected]>

import maidenhead as mh
import simplekml
import psycopg2
import logging
import pyproj


def main():
    trip_km = 0
    balloon = "LY1BWB"
    launch_date = "2021-11-09T07:00:00Z"
    kml = simplekml.Kml()
    ls = kml.newlinestring(name="LY1BWB path")
    try:
        conn = psycopg2.connect(
            "host=logs2.wsprdaemon.org dbname=wsprnet user=wdread password=JTWSPR2008"
        )
    except psycopg2.OperationalError as err:
        logging.error("PostgreSQL connect error: " + str(err))
        conn = None
    cursor = conn.cursor()
    cursor.execute(
        'SELECT "Grid", "wd_time" FROM (select DISTINCT ON ("Grid") "Grid", "wd_time" \
                  FROM spots WHERE "CallSign"=\''
        + balloon
        + "' AND \"wd_time\" > '"
        + launch_date
        + '\' ORDER BY "Grid", "wd_time" ASC) dt ORDER BY "wd_time" ASC;'
    )

    sqldata = cursor.fetchall()
    conn.close()

    for idx, row in enumerate(sqldata):
        from_square = row[0]
        if idx < len(sqldata) - 1:
            to_square = sqldata[idx + 1][0]
            to_time = sqldata[idx + 1][1]
            (x1, y1) = mh.to_location(from_square)
            (x2, y2) = mh.to_location(to_square)
            kml.newpoint(name=to_square, description=to_time, coords=[(y2, x2)])
            ls.coords.addcoordinates([(y2, x2)])
            geo = pyproj.Geod(ellps="WGS84")
            _fw, _bg, distance = geo.inv(y1, x1, y2, x2)
            distance_km = distance / 1000
            print(
                "%s: %.2f,%.2f --> %.2f,%.2f (%d km)."
                % (to_time, x1, y1, x2, y2, distance_km)
            )
            trip_km = trip_km + distance_km
    print("Total trip length for %s: %d km" % (balloon, trip_km))
    kml.save("trip.kml")


main()