Thanks for the answers.
For the coordinates, I think it will be usefull for a part of a land.
Example : I'm living in France and I want to prepare some walks in a part of Alps, zoom 17. Preparing not in the same time, so I must return on the same part of the map but the memory of position is lost.
If I have a system like in "Placemarks", "Project New Placemark", "Source Point Type (center of screen or Mark)", I can create a placemark for centering the favorite. In that case, the choice is open enter the center of the screen or a placemark.