Long direction is the meaning of a word, which is often used to describe the specific direction of something or a scene. In visual arts, the long direction usually refers to the part of the picture perpendicular to the horizontal direction. For example, in stereoscopic images, we can see that the size of the object is different in the front and back direction, which is the change of the object in the long direction.

The long direction can also refer to the extension direction of a place or region. For example, urban planning, we often hear words such as long-term transportation planning or long-term urban development. These words are determined by the direction designated by the long direction, so as to better plan, utilize and develop the resources in these areas.

In mathematics or statistics, the long direction refers to the changing trend of a group of data or variables on the time axis. For example, when counting the sales of a company, we can observe its long-term changing trend according to the monthly or quarterly time series, so as to make better decisions and plan the business development direction. Long-term direction is very important for data analysis and business forecast.