Draw it as 12 cm wide, and 8 cm wide is more appropriate.

The ratio is12:12000 =1:1000.

The ratio is 1: 1000.

According to the size of the picture you want to draw, have a rough size first.

Then find the scale.

The length of this topic is 120m, and the size of the 32-inch paper we usually use on the drawing is almost 12 cm.

If it is drawn as 1.2 cm, it is too small, and 120 cm is too big, so 12 cm is more suitable.

Proportion is to divide the size on the drawing by the actual size.

The size of this picture depends on your own consideration.