Isolines generalization |
|
|
1) removing or reforming isolines; 2) removing bergstrichs of removed isolines; 3) removing titles of removed isolines; 4) removing or reforming point objects with absolute elevation.
Parameters of isolines generalization at setting are saved in a file with the ILG extension. ILG file structure: - section of general parameters [ILG]; - section of codes of thick isolines [ObjIsolineThick]; - section of codes of principal isolines [ObjIsolineMain]; - section of codes of additional isolines [ObjIsolineAdd]; - section of codes of auxiliary isolines [ObjIsolineAux]; - section of bergstrichs codes [ObjBerg]; - section of codes of isolines titles [ObjTitle]; - section of codes of point objects with absolute elevation [ObjDot]; - section of object codes banning the removal of point objects with absolute elevation [ObjDotBan].
During processing, some of the isolines can be deleted or reformed to other types of isolines. Types of processed isolines are contained in the bookmarks of the dialog: Thick, Principal, Additional, Auxiliary. At processing of isolines the value of elevation from semantics which code is set by parameter of dialog Semantic code Absolute elevation is requested. At removal of isolines of small length and the area the parameters are used specified in group the Conditions of isoline removing: Minimum length, Minimum square, Remove isolines crossing sheet border. At reforming the type of isolines the continuity of the isoline location (on a land, on glaciers, on landslips, etc.) is provided. The metric of the resulting isolines can be smoothed. To do this, when setting parameters, you must set the Coefficient of smoothing (number greater than 0 and less than 1, the recommended value is 0.5). If the coefficient is zero, the metric is not smoothed. During processing, bergstrichs are deleted, which do not belong to any isoline line of the sheet. Such bergstrichs remain on the map after the removal of isolines. The types of processed bergstrichs are contained in the page of the Bergstrichs dialog box. To determine the belonging, the dialog parameter the Maximum distance from isoline to bergstrich is used. During the processing, the titles of isolines that do not belong to any isoline of the sheet are deleted. Such titles remain on a map after removal of isolines. Types of processed titles are contained in the page of dialog the Isoline titles. To determine the belonging, the dialog parameter the Maximum distance from isoline to title is used. If in processing's parameters the mode is set Create additional, then the additional isolines received as a result of processing can be rarefied, that is decrease in density of additional isolines can be executed. If the Create additional mode is specified in parameters of processing, the additional isolines obtained as a result of processing can be rarefied, that is, the density of additional isolines can be reduced. To reduce the density of additional isolines, when setting the parameters, you must set the Coefficient of density reduction (a number greater than 0 and less than 10, the recommended value is 2). At zero value of the coefficient, the density reduction is not performed. In the process of rarefaction, the length of the additional isoline may decrease. If the length obtained is less than the Minimum length of additional isoline, the additional isoline is deleted. If the obtained length is less than the Minimum length of additional isoline, the additional isoline is deleted. The process of reducing the density of additional isolines is displayed by a separate line of progress. When processing point objects with absolute elevation, some point objects can be deleted or reformed to objects of another type. Types of processed point objects are contained in the page of the Dots dialog. At processing, the Density (dots / sq.dm) parameter is used.
Processing of point objects with absolute elevation.
|
In the process of isolines generalization it is performed: