The terms “panoramic view” and “full panoramic view” come from the English word “panorama” and should be translated as “broad view”. The earliest panorama images refer to hand-drawn wide-angle landscape paintings, or we can call them wide-angle shots. However, in terms of image ratio, a wide-angle shot has a width way greater than its height, creating a strong depth perception.
The field of view captured in broad-view photos can only reach as large as 180°, mainly because human eyes see the world through “perspective projection”, which is limited to a 180° field of view. We need to adopt different projection methods to display an image with a field of view larger than 180°. Normal people cannot appreciate and accept the projection methods that create a field of view exceeding 180° (these methods cause image distortion). So, 360° panoramic photography is not applied substantially before the development of computer graphics.
Panoramic photography (360°) applications have only started to appear in recent years, especially after people have drastically improved computing power and after personal computers can cope with computer processing for real-time image conversion projection. A photo that covers a view angle of 360° in the horizontal direction is called a panoramic photo or 360° panoramic photo. We also call these photos full panoramic photos (Full Panorama) because a full circle is 360°.
Panorama (360°)/full panorama can be defined only by the angle of view in the horizontal direction, not in the vertical direction (vertical angle). Therefore, from the perspective of the vertical angle, panoramic photos covering the zenith and nadir areas also cover another circumference of 360°. Adding the 360° horizontal and 360° vertical field of view together generates a 720° angle of view and hence the term 720° panorama.
However, “720° panorama” is not an official term, and no one from other countries or academic circles names this type of photo this way. This term sounds fancy yet describes this type of photo unprofessionally. We prefer to call these photos “spherical panorama” for this type of panoramic photo.