It is possible to say that in ObjectLand map features are built mainly from points and segments of straight lines connecting these points. Coordinate transformation of features means transformation of coordinates of their vertices. This issue should be examined in more detail.
Transformation of a point feature means moving of a base point of this feature. Display of feature symbol as well as such feature parameters as size, zoom threshold and rotation angle are not changed.
Transformation of a line feature means moving of all feature vertices in accordance with the transformation rule. The vertices will still be connected by straight-line edges even if nonlinear coordinate transformation was performed.
For an area feature transformation of all its boundaries similarly as the transformation of line features is performed, that is, by moving vertices.
A text feature is transformed by moving its base point, that is, top left corner of the box bounding the text. The remaining feature parameters are not changed.
The issue about transformation of image features is more complicated. When performing the operation of coordinate transformation, image features can be included in the set of transformed features together with features of other spatial categories. Actually, control points of raster georegistration undergo transformation, as well as vertices of polygons specifying image feature boundaries. Thus, any coordinate transformation of an image feature, including nonlinear, results in changing of feature georegistration to the map and transformation of its boundaries. There is also a separate operation of transformation of image features provided in the system. It performs affine or nonlinear transformation of raster graphics itself keeping the position of the feature on the map unchanged.
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