Convert GPS data points from Seeedstudio LoRaWAN tracker from TTN MQTT to GeoJSON

main.py

import json
from datetime import datetime

# https://jsoneditoronline.org/#left=local.kuvewa
# https://files.seeedstudio.com/products/SenseCAP/SenseCAP_Tracker/SenseCAP_Tracker_T1000-AB_User_Guide.pdf
# https://github.com/Seeed-Solution/SenseCAP-Decoder/blob/main/T1000/TTN/SenseCAP_T1000_TTN_Decoder.js


file = open("data.log", "r")
lines = file.readlines()

count = 0
positions=[]
for line in lines:
    try:
        obj = json.loads(line)
        if obj["end_device_ids"]["device_id"] == "tracker-t1000a-1":
            uplink_message = obj["uplink_message"]
            rx_metadata = uplink_message["rx_metadata"][0]
            received_at = rx_metadata["received_at"]

            uplink_message_settings_time = uplink_message["settings"]["time"]
            uplink_message_received_at = uplink_message["received_at"]
            rx_metadata_time = rx_metadata["time"]
            rx_metadata_gps_time = rx_metadata["gps_time"]
            rx_metadata_received_at = rx_metadata["received_at"]
            rx_metadata_timestamp = rx_metadata["timestamp"]

            rssi = str(rx_metadata["rssi"])
            snr = str(rx_metadata["rssi"])

            timestamp = 0
            try:
                timestamp = obj["uplink_message"]["decoded_payload"]["messages"][0][0]["timestamp"]
            except:
                pass



            decoded_payload = obj["uplink_message"]["decoded_payload"]
            messages = []
            if decoded_payload.get("messages") != None:
                messages = decoded_payload["messages"]
            error_message = ""
            if decoded_payload.get("errMessage") != None:
                error_message = decoded_payload["errMessage"]


            if len(messages) > 0 or len(error_message) > 0:
                print("[" + str(count) + "]" + received_at + " --> " + datetime.fromtimestamp(timestamp / 1000).strftime(
                    '%c') + " -- RSSI: " + rssi + ", SNR = " + snr)
                count = count + 1

                messageCount = 0
                for message in messages:
                    latitude = None
                    longitude = None
                    for measurement in message:
                        print("\t[" + str(messageCount) + "] " + measurement["measurementId"] + " = " + str(measurement["measurementValue"]))
                        if measurement["measurementId"] == "4197":
                            longitude = measurement["measurementValue"]
                        if measurement["measurementId"] == "4198":
                            latitude = measurement["measurementValue"]
                    if latitude is not None and longitude is not None:
                        positions.append({"timestamp": timestamp, "longitude": longitude, "latitude": latitude})

                    messageCount = messageCount + 1
                if len(error_message) > 0:
                    print("\tError : " + error_message)
    except:
        pass

filePositions = open("positions.txt", "w")

filePositions.write("{\n    \"type\": \"FeatureCollection\",\n\t\"features\": [\n\t\t{\n")
filePositions.write("\"type\": \"Feature\",\n\"geometry\": {\n\"type\": \"MultiLineString\",\n\"coordinates\": [\n[\n")

print("timestamp;long;lat")
#filePositions.write("timestamp;long;lat\n")
c = 0

positions_sorted = sorted(positions, key=lambda p: p["timestamp"])

for position in positions_sorted:
    #filePositions.write(datetime.fromtimestamp(position["timestamp"] / 1000).strftime('%c') + ";" + str(position["longitude"]) + ";" + str(position["latitude"]) + "\n")
    if c < len(positions) - 1:
        filePositions.write("[" + str(position["longitude"]) + "," + str(position["latitude"]) + "],\n")
    else:
        filePositions.write("[" + str(position["longitude"]) + "," + str(position["latitude"]) + "]\n")
    print(datetime.fromtimestamp(position["timestamp"] / 1000).strftime('%c') + ";" + str(position["longitude"]) + ";" + str(position["latitude"]))
    c = c+1

filePositions.write("]]}}]}")

filePositions.close()