Offten happens that our photos don't have geo coordinates saved in EXIF data. It may be because of many factors: camera doesh't have built-in GPS receiver, GPS didn't fixed position or GPS was disbled to save battery. I had such problem and dindn't found a simple method for adding lat/lng coordinates (geotags) to exif data, so I decided to make it as siple as possible.
Best tool for editing EXIF data in photo images (eg. jpg) is ExifTool. However to use it one has run single command for every photo. It is no so bad bucause you can script it. Worst part is to get lat/lng coordinates for every photo. It can be very time consuming thats why this tool was developed.
This tool simplifies adding geographical coordinates to photos. But it is not magical automat. It will require some work from you. Most important thing is to know where the photo was taken. Second thing is at least basic knowledge of console (windows or linux - depending on your operating system).
Tool consist of two columns. In first one (left) there is a map. In second one there is output (data window). Now only thing you have to do is to drag and drop your image on map to place where it was taken. It will generate ready to run exiftool command which will add appropriate Exif tags. You can drop many photos at once. It is best practice to copy all data to .bat (.sh) file and run it in directory with photos. It requires as much free space as photos are taking because exiftool does photo's backup by default. You can delete those backups after finishing editing.
Click here to run my tool - lat/lng exif editor in photos