Support for Drupal 7 is ending on 5 January 2025—it’s time to migrate to Drupal 10! Learn about the many benefits of Drupal 10 and find migration tools in our resource center.
There isnt a administration way to change it but you can change with css.
Add this code to your theme:
.google_map_field_display {
height: 300px;
width: 500px;
}
change height and width to fit the size you need.