Geolocation
Oqapy can help you to write the geographical coordinates of a picture into its metadata.
There's two tools for that, the map located into the image infos page and, if you have a GPX file, the geolocation dialog box callable from the Global menu
Set the coordinate with the Geolocation tool box
The map viewer can use two map servers: OpenStreetMap and GoogleMap, you can change the server with the buttons located into the header bar of the tool box .
The map can be moved or zoomed with the mouse.
When the map is changed, the coordinates of the center of the map are updated.
Click on the button Apply to write the coordinates into the picture's metadata.
If the current image is already geolocated, the button Apply is locked, click on the button to unlock it.
The button Expand call the Extended Map.

Set the coordinate with the Geolocation dialog box
The Geolocation tool is located into the menu Tools.
Into the line edit, enter the path of the GPX file.
The tracks found into the file are displayed into a table view, if you select a track, the map, on the right side, shows you the location of the first coordinate's point of this track and the number of the points appears under the table.
Now, you must set the hour of the camera, you have four choices:
GMT: means the time UTC + 0.
Locale: is the time of the computer.
Other: if you need to apply a correction in hours or in minutes.
Choose the first picture: if you don't know the time of the camera.
Click on the Sort button.
The program look into the picture's folder for the images wich have a creation date and time into the range defined by the start time and the end time of the coordinate's track.
The first image appears into the viewer, if you have set the option "Choose the first picture" you can navigate into the list of the pictures and select the first image that was taken at the time of the first coordinate's point with the button Select.
To finish, click on the button Apply.
The Extended Map dialog
At the top of the window you can choose the map server and you can set the map to a predefined location with the "Go to" combo box.
When the map is changed, the Geolocation tool box is updated.
Create a predefined location
Move the map to the desired place.
Enter a name into the line edit "Save as", use a simple name, i.e. the name of the city.
Enter a description, this will appear into a tool tip when you open the "Go to" combo box, so you may be more verbose.
Click on the button Create.