North-Up Image Correction for DJI Drone Photos

dji-rotate.md

Overview

This script automatically rotates DJI drone images so that North is at the top, based on the Gimbal Yaw Degree stored in the image metadata.

How It Works

• Extracts Gimbal Yaw Degree (the camera's direction when the photo was taken).
• Computes the correct rotation using the formula:

Rotation Angle = 180 - Gimbal Yaw Degree

• Rotates the image accordingly so that North is correctly up.

⠀Requirements Ensure you have the following installed: ExifTool (for extracting metadata)

brew install exiftool # macOS

sudo apt install libimage-exiftool-perl # Linux

ImageMagick (for rotating images)

brew install imagemagick # macOS

sudo apt install imagemagick # Linux

Usage

Rotate a Single Image

exiftool -GimbalYawDegree -s3 "input.jpg"
ROTATION_ANGLE=$(exiftool -GimbalYawDegree -s3 "input.jpg" | awk '{print 180 - $1}')
convert "input.jpg" -rotate "$ROTATION_ANGLE" "output_NorthUp.jpg"

Batch Process All DJI Images in a Directory

for img in DJI_*.jpg; do
     ROTATION_ANGLE=$(exiftool -GimbalYawDegree -s3 "$img" | awk '{print 180 - $1}')
     convert "$img" -rotate "$ROTATION_ANGLE" "${img%.*}_NorthUp.jpg"
     echo "Processed: $img → ${img%.*}_NorthUp.jpg"
done

Notes

• Works for DJI drone images that contain Gimbal Yaw Degree metadata.
• If GimbalYawDegree is missing, the script will not rotate the image.
• The script assumes no extreme camera tilt; it only corrects rotation based on yaw.

Example Output

Before correction:

• Gimbal Yaw Degree: -65.3° (Camera was pointing ~WNW)

⠀After correction:

• Image rotated 65.3° counterclockwise to align North at the top.