Locks layer in burst-mode operation.
// Delphi public procedure Lock; virtual;
// C++ Builder public: virtual void Lock(void);
Extent for viewer will not be refreshed (i.e., extent will not be recalculated).
Calling Lock, disables any projection-level operations. AddPoint/GetPoint will operate in the layer's native coordinates.
See TGIS_Shape.Lock for a similar example.
Use this method to lock a shape for burst-mode operation. After locking, AddPoint will be much faster. But please remember that the shape, layer and viewer extent will be updated after the call to Unlock. Lock also can be used to temporarily disable projections, i.e., reading/setting points will be done without any projections.
Unlock method MUST be called if Lock was used.