Forming horizontals

During construction of contours it is consistently carried out:

- construction of sections of a relief;

- filling a matrix of displacements;

- tracking the metrics of isoline of a relief on a matrix of displacement;

- quality assurance of the metrics of the traced isoline;

- record of a contour into an output file.

The purpose of sections construction is creation of a technological file of sections (*.sec) in which the information on the constructed sections is stored. Construction of sections is carried out with the step specified as height of section of a relief. The matrix of heights is conditionally dissected by planes multiple to height of section. Points of crossing of a plane and MRH are sections of a relief. The file of sections represents set of points on district, heights in which are multiple to height of section of a relief, and coordinates are multiple to lines and columns of MRH. Each element of a file of displacement contains corresponding displacement from node of a matrix. Displacements are always positive, do not exceed discreteness of MRH and show distance from node of a matrix to the left or upwards (on a line or on a column).

The received set of sections is the initial information for tracking contours. Tracking of contours is carried out on a matrix of displacement by dimensions conterminous with MRH. In a cycle for each height of section the matrix of displacement is created in which nodes the size of displacement from MRH node up to a point with the height corresponding to height of a contour is contained.

The quantity of columns of a displacements matrix is equal to quantity of MRH columns, and quantity of lines is twice more than quantity of MRH lines. It is made to place the information on sections between lines.

As on the crossed relief the form of the traced horizontals turns out angular and as it is possible folded  (as a loop) crossing of horizontals, additional processing of horizontals is carried out. Are consistently executed:

- deleting horizontals, which length is less than specified;

- metrics filtration;

- smoothing of horizontals.

In a matrix there can be erroneous values of heights. In this case the small closed contours will be generated, for their deleting it is necessary to specify necessary length in mm of a map. The program will automatically delete contours, which length is less than specified one.

Filtration is executed for preparation of horizontals for smoothing. The primary task is elimination of the paired metrics points distant from each other on the distance specified in meters as a filtration step of the horizontals metrics. User must independently supervise the size of filtration step. Changing its value it is possible to obtain smoother forms of horizontal. Besides, the filtration can eliminate sawtooth contours.

Smoothing of horizontals is carried out with the purpose of giving to the horizontals metrics of smoother form, by addition of metrics points by interpolation method of their planned position. Smoothing can be executed by various methods: a spline interpolation, interface of parabolas, curve Bese.

The traced horizontal is placed into file of the user map with the following classification codes described in map classifier:

21200000 - principal horizontal;

21100000 - thickened horizontal;

21300000 - supplementary horizontal.

By default objects of the user map are coded according to the classifier of the basic map from which matrix data are opened. If matrix data are opened only, MtwToMap.rsc classifier is used by default. If the specified classification codes are not present in the classifier, all horizontals will be written down into System layer as object: Marking of linear.