To create a set: section and its external contours

The mode is intended for formation of the spatial data set uniting several external contours of one ground area. It can be single land tenure or the multiplanimetric ground areas. Before the execution of operation it is necessary to mark on a map all contours of one ground area. After a choice of a mode, it is necessary to specify by double click of the mouse among the marked objects the object, which will be appointed by the main one. The main object of a set is used by the program at reading and writing the attributive data of the ground area.