Transformation of features' coordinates according a given transformation rule is one of important tools provided by the ObjectLand system. This rule is determined via specifying both old and new values of coordinates for a certain set of control points and selecting a variant of transformation most suitable in a specific case. The user is provided with two essentially different possibilities:
Coordinate transformation can be performed once resulting in setting new values of coordinates for involved map features. This kind of transformation will be considered in detail in the chapter 20 “Transformation of coordinates”.
The transformation can be linked with a specific theme and be performed “on the fly” each time the theme is displayed. In this case the map features retain their original coordinate values, only their coordinates on display in the given theme are changed. In other themes the same features will be displayed without changes.
The following tasks requiring coordinate transforming on displaying themes can be mentioned among others:
combined display of layers belonging to different maps with different coordinate systems;
correcting inaccurately measured coordinates of features in accordance with more precise values of a certain number of landmark points, especially when it is impossible to perform a permanent feature transformation in the absence of a right to change an EDB layer.
Detailed description of all transformation variants and of corresponding settings is given in the chapter 20 “Transformation of coordinates”.
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