The article presents the author’s method of scale determining of cartographical chart. The worked out method permits on scale defining on the base on resolution of source imagery, precision of location and internal geometry of situational details as well as the defining of interpretation aim. In present study authors introduce a new attitude to cartographical study of seaports. It relies on very high resolution imageries using to create a orthophotomap and regards it as a final product instead of product attending to updating other maps