gps integration - dwilson2547/wiki_demo GitHub Wiki
To add GPS EXIF data to images captured with picamera2, you'll need to use the exif parameter in your capture method and format the GPS coordinates properly. Here's how you can do it:
First, make sure you have the necessary packages:
pip install exif piexifHere's a complete example showing how to add GPS EXIF data:
#!/usr/bin/env python3
import time
import piexif
from picamera2 import Picamera2
from fractions import Fraction
def decimal_to_dms(decimal_degrees):
"""
Convert decimal degrees to degrees, minutes, seconds format for EXIF
Returns tuple of ((degrees, 1), (minutes, 1), (seconds, 100))
"""
degrees = int(abs(decimal_degrees))
minutes_float = (abs(decimal_degrees) - degrees) * 60
minutes = int(minutes_float)
seconds = (minutes_float - minutes) * 60
# Convert to rational numbers (fractions) as required by EXIF
return ((degrees, 1), (minutes, 1), (int(seconds * 100), 100))
def create_gps_exif(latitude, longitude, altitude=None):
"""
Create GPS EXIF data dictionary
latitude: decimal degrees (positive for North, negative for South)
longitude: decimal degrees (positive for East, negative for West)
altitude: meters above sea level (optional)
"""
# Determine hemisphere references
lat_ref = 'N' if latitude >= 0 else 'S'
lon_ref = 'E' if longitude >= 0 else 'W'
# Convert to DMS format
lat_dms = decimal_to_dms(latitude)
lon_dms = decimal_to_dms(longitude)
gps_dict = {
piexif.GPSIFD.GPSLatitudeRef: lat_ref,
piexif.GPSIFD.GPSLatitude: lat_dms,
piexif.GPSIFD.GPSLongitudeRef: lon_ref,
piexif.GPSIFD.GPSLongitude: lon_dms,
piexif.GPSIFD.GPSMapDatum: "WGS-84",
}
# Add altitude if provided
if altitude is not None:
alt_ref = 0 if altitude >= 0 else 1 # 0 = above sea level, 1 = below
gps_dict[piexif.GPSIFD.GPSAltitudeRef] = alt_ref
gps_dict[piexif.GPSIFD.GPSAltitude] = (int(abs(altitude) * 100), 100)
return gps_dict
def capture_image_with_gps(latitude, longitude, altitude=None, filename="image_with_gps.jpg"):
"""
Capture an image with GPS EXIF data using PiCamera2
"""
# Initialize camera
picam2 = Picamera2()
# Configure camera (you can adjust these settings as needed)
config = picam2.create_still_configuration()
picam2.configure(config)
# Start camera
picam2.start()
# Allow camera to warm up
time.sleep(2)
try:
# Create GPS EXIF data
gps_exif = create_gps_exif(latitude, longitude, altitude)
# Create complete EXIF dictionary
exif_dict = {
"0th": {},
"Exif": {},
"GPS": gps_exif,
"1st": {},
"thumbnail": None
}
# Convert to bytes
exif_bytes = piexif.dump(exif_dict)
# Capture image with EXIF data
picam2.capture_file(filename, exif=exif_bytes)
print(f"Image captured with GPS data: {filename}")
print(f"Location: {latitude}, {longitude}")
if altitude:
print(f"Altitude: {altitude}m")
finally:
# Clean up
picam2.stop()
# Example usage with real GPS coordinates
if __name__ == "__main__":
# Example coordinates (Big Ben, London)
lat = 51.5007
lon = -0.1246
alt = 11 # meters above sea level
# Capture image with GPS data
capture_image_with_gps(lat, lon, alt, "photo_with_location.jpg")
# You can also capture without altitude
capture_image_with_gps(lat, lon, filename="photo_basic_gps.jpg")If you want to get actual GPS coordinates from a GPS module, here's how you can integrate it:
#!/usr/bin/env python3
import serial
import pynmea2
import time
from picamera2 import Picamera2
import piexif
from fractions import Fraction
class GPSReader:
def __init__(self, port='/dev/ttyUSB0', baudrate=9600):
"""
Initialize GPS reader for NMEA GPS modules
Common ports: /dev/ttyUSB0, /dev/ttyAMA0, /dev/serial0
"""
self.ser = serial.Serial(port, baudrate, timeout=1)
def get_gps_data(self, timeout=30):
"""
Read GPS data until we get a valid fix
Returns: (latitude, longitude, altitude) or None if timeout
"""
start_time = time.time()
while time.time() - start_time < timeout:
try:
line = self.ser.readline().decode('ascii', errors='replace').strip()
if line.startswith('$GPGGA') or line.startswith('$GNGGA'):
msg = pynmea2.parse(line)
if msg.latitude and msg.longitude:
lat = float(msg.latitude)
lon = float(msg.longitude)
# Convert from NMEA format if needed
if msg.lat_dir == 'S':
lat = -lat
if msg.lon_dir == 'W':
lon = -lon
# Altitude (convert from string to float if available)
alt = float(msg.altitude) if msg.altitude else None
return lat, lon, alt
except (pynmea2.ParseError, ValueError, UnicodeDecodeError):
continue
return None
def close(self):
self.ser.close()
def capture_with_live_gps(filename="gps_photo.jpg"):
"""
Capture photo with live GPS data from connected GPS module
"""
gps = GPSReader() # Adjust port if needed
print("Waiting for GPS fix...")
gps_data = gps.get_gps_data(timeout=60)
if gps_data:
lat, lon, alt = gps_data
print(f"GPS fix acquired: {lat}, {lon}, altitude: {alt}m")
# Use the previous capture function
capture_image_with_gps(lat, lon, alt, filename)
else:
print("Could not get GPS fix within timeout period")
gps.close()
# Alternative: Using gpsd daemon (if you have it set up)
def get_gps_from_gpsd():
"""
Alternative method using gpsd daemon
Requires: pip install gpsd-py3
"""
try:
import gpsd
# Connect to the local gpsd
gpsd.connect()
# Get a GPS reading
packet = gpsd.get_current()
if packet.mode >= 2: # 2D fix or better
return packet.lat, packet.lon, packet.alt if packet.mode >= 3 else None
else:
return None
except ImportError:
print("gpsd-py3 not installed. Use: pip install gpsd-py3")
return None
except Exception as e:
print(f"GPS error: {e}")
return None
# Example usage
if __name__ == "__main__":
# Method 1: Using direct serial connection to GPS module
# capture_with_live_gps("live_gps_photo.jpg")
# Method 2: Using gpsd (uncomment if you have gpsd running)
# gps_data = get_gps_from_gpsd()
# if gps_data:
# lat, lon, alt = gps_data
# capture_image_with_gps(lat, lon, alt, "gpsd_photo.jpg")
pass-
EXIF Format: GPS coordinates in EXIF must be in degrees/minutes/seconds format with rational numbers (fractions), not decimal degrees.
-
PiCamera2 Integration: Use the
exifparameter incapture_file()method to embed the EXIF data. -
Required Packages:
-
piexiffor creating EXIF data -
pynmea2for parsing GPS NMEA sentences (if using GPS module) -
pyserialfor GPS module communication
-
-
GPS Module Connection: Most USB GPS modules appear as
/dev/ttyUSB0. For GPIO-connected modules, try/dev/ttyAMA0or/dev/serial0.
You can verify the GPS data was embedded correctly:
# Test script to read EXIF data
import piexif
from PIL import Image
def read_gps_exif(filename):
img = Image.open(filename)
exif_dict = piexif.load(img.info['exif'])
if 'GPS' in exif_dict:
gps_data = exif_dict['GPS']
print("GPS EXIF data found:")
for key, value in gps_data.items():
print(f" {piexif.GPSIFD(key).name}: {value}")
else:
print("No GPS data found in EXIF")
# Test your captured image
read_gps_exif("photo_with_location.jpg")The GPS data will then be visible in photo viewers and mapping applications that support EXIF GPS data.