Please be aware that only 'comment' values are written to the file if it's a JPEG. This means that any other data, such as GPS data or Exif data can be 'modified' but will not be written to the file. This might change in the future, but it hasn't change in 2 years.
For reference.
https://github.com/mkoppanen/imagick/issues/124
https://github.com/ImageMagick/ImageMagick/issues/55