Matching of horizontals with linear objects of hydrography

When combining the layers of vector map containing objects of hydrography and objects of a relief, received from different sources (by different technology) there is a problem of location mismatch of objects of a relief and objects of hydrography.

This task is intended for bringing in conformity of contours of horizontals concerning contours of the linear rivers. Thus, the artificial local deformation of horizontals is carried out:

-        combination of extremums of horizontals sections with contours of the rivers;

-        forming the extremums of horizontals sections in intersection points of contours of horizontals and rivers (at the extremums absence).

This task should be performed only after control of absolute heights, so as at the matching of horizontals with linear objects of hydrography the direction of a digitizing of horizontals and objects of hydrography is considered.

During processing, the points of intersection of a horizontal with the next linear object of hydrography are defined. If the number of intersection points is more than 1, the message in the errors log is placed and processing the horizontal is stopped.

Matching of horizontals with linear objects of hydrography is carried out by the module horadapt.dll which is called through the Run Application item of the Tools menu.

The program works in the dialog mode which window consists of several parts:

-        path of access and the name of files (input map, file of settings);

-        Horizontals and Hydrography tables;

-        parametres of customizing the processing;

-        information fields about the status of map processing;

-        operating keys.

Horizontals table should contain the following objects:

-        Horizontals thickened;

-        Horizontals main;

-        Horizontals additional.

Hydrography table should contain the following objects:

-        Rivers, brooks constant;

-        Rivers, brooks drying up.

Parametres of customizing the processing:

-        Maximum admissible displacement of a horizontal (in millimetres on a map);

-        Relative length of deformation (a multiplier to the field Maximum admissible displacement);

-        Coefficient of deformation;

-        Form the thalwegs;

-        Thalweg length (in millimetres on a map);

-        Thalweg width (in millimetres on a map).

The maximum admissible displacement of a horizontal defines the maximum length of displacement vector of an existing extremum of a horizontal's section to a river contour.

The deformation coefficient defines degree of deformation function.

Form the thalwegs - at the enabled parameter the extremums of horizontals sections in intersection points of contours of horizontals and rivers (at the extremums absence) will be formed. In this case the Width parameter defines width of a formed thalweg (in half of width into each side from the extremum), and the Length parameter defines depth of a formed thalweg.

All settings of mode the Matching of horizontals with linear objects of hydrography are saved in a file with IHA extension.

Upon termination of process it is necessary to check quality of processing (Map Editor - View errors). The View errors log can contain the following messages explaining the reasons for absence of processing:

- «Metrics of a horizontal less than two points»,

- «Repeated crossing of horizontal A and river B - № 1»,

- «Repeated crossing of horizontal A and river B - № 2»,

- «Point of intersection of horizontal A with river B is close to the beginning»,

- «Point of intersection of horizontal A with river B is close to the end»,

- «Points of intersection of horizontal A with rivers are too close»,

- «May be error in direction of digitizing of horizontal A or river B»,

- «Too big divergence of contours of river A and horizontal B»,

- «Error in determining the vector of deformation of horizontal A to the river B»,

- «Section of river A has a complex form»,

- «Length of displacement vector of section top for horizontal A is exceeded»,

- «Section top of horizontal A is close to the beginning»,

- «Section top of horizontal A is close to the end».