Isolines depression

Process of depression (generalization) of isolines is a transformation of horizontals according to the established conditions.

Dialog contains the table of processed objects of a relief (an isoline, bergstriches, titles of isolines) and fields of editing:

 - semantic code "ABSOLUTE ELEVATION";

 - contour interval of a derivative map;

 - tolerance of processing, determining the conditions of deleting an isoline (the minimal length and square);

 - tolerance of processing, defining a belonging of bergstriches and titles to an isoline (Conditions of correspondence to isoline).

In the column the Horizontal thick (of Isoline table) it is necessary to choose type of object of the Horizontal thick from the classifier, in the columns the Horizontal principal and Horizontal additional - the corresponding types. The choice of objects is carried out by double click of the left mouse button in the filled column.

Field's value the Semantic code "Absolute elevation" is used for definition of processed objects. If the object specified in the isolines table of dialog, does not contain semantics with the specified code the object is not processed.

Contour interval of a relief is set from the settings file of formation of a nomenclature sheet of a derivative map (file with extension IUN).

Values of fields the Minimal length, the Minimal square define conditions of isoline deleting.

If length of an isoline is less than the minimal length or the area of the closed horizontal is less than the minimal area the isoline is deleted.

During generalization of a relief together with deleted horizontals the bergstriches and titles belonging to them are deleted also.

Belonging of a bergstrich to a horizontal depends on the field value the Maximal distance from an isoline up to a bergstrich, defined at customizing parameters of a relief's generalization. If the distance from the first point of the bergstrich metrics up to a current point of the metrics of a horizontal is less than the distance specified in the field then the bergstrich belongs to the horizontal. Recommended value of the admission of processing the Maximal distance from isoline up to a bergstrich is 0.05 mm of a map.

Belonging of the title to a horizontal depends on the field value the Maximal distance from isoline up to the title. The title belongs to a horizontal if the height from the text of the title coincides with height from semantics of a horizontal and if distance from the first point of the metrics of the title up to a horizontal is less than distance specified in the field. Recommended value of the admission of processing the Maximal distance from isoline up to the title is equal to 0.1 mm of a map.              

If length of a horizontal is less than threshold value (tolerance) of length or the area of the closed horizontal less than threshold value of the area the horizontal is deleted. If the absolute height of a horizontal is not multiple to half of contour interval of a derivative map (an additional horizontal of an initial map) the horizontal is deleted. If the absolute height of a horizontal is multiple to half of contour interval of a derivative map the horizontal will be converted into additional one.

The analysis of quality of a derivative map is carried out on the basis of the error log (messages) received upon termination of forming a nomenclature map sheet of derivative scale, in dialog Map Editor/View error.

Processing of bergstriches is carried out after processing horizontals. The object of an initial map is processed as a bergstrich.

For each bergstrich the horizontals of a sheet on which there is a bergstrich are scanned. If the bergstrich does not belong to any horizontal it is deleted.

The belonging of a bergstrich to a horizontal is defined by coincidence (close) of the first point of the bergstrich metrics and a current point of the metrics of a horizontal. Thus the admission of processing, defining the belonging a bergstrich to an isoline, is used.

Processing the titles of horizontals is carried out after processing the horizontals. The object of an initial map is processed as the title of a horizontal.

For each title the horizontals of a sheet on which there is a title are scanned. If the title does not belong to a horizontal it will be deleted.

Belonging of the title to a horizontal is defined by coincidence of value of absolute height from the text of the title and value of height of a horizontal, and also on affinity of the first point of the title metrics and a current point of the metrics of a horizontal. Thus the admission of processing defining a belonging of the title to an isoline is used.