import csv
import sys

def csv_to_gpx(csv_filename):
    with open(csv_filename, newline='', encoding='utf-8') as csvfile:
        reader = csv.DictReader(csvfile)
        
        print('<?xml version="1.0" encoding="UTF-8"?>')
        print('<gpx version="1.1" creator="CSV to GPX Converter">')
        print('  <trk>')
        print('    <trkseg>')

        for row in reader:
            print(f'      <trkpt lat="{row["lat"]}" lon="{row["lng"]}">')
            print(f'        <ele>{row["elevation"]}</ele>')
            print('      </trkpt>')

        print('    </trkseg>')
        print('  </trk>')
        print('</gpx>')

if __name__ == "__main__":
    if len(sys.argv) != 2:
        print("Usage: python {}.py [input_file.csv]".format(__name__))
        sys.exit(1)

    csv_to_gpx(sys.argv[1])