The category "<pan_operation>" can be expressed as follows:

<pan_operation>

<pan_verb> <compass_direction>

<pan_verb> <compass_direction> <general_distance-measure>

<pan_verb> <general_distance-measure> <compass_direction>

<pan_verb> <general_distance-measure> <screen_direction>

<pan_verb> <screen_direction>

<pan_verb> <screen_direction> <general_distance-measure>