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Geometry allocation
Points
Ambiguity exists if a regular grid is used for storing single points, because a point can occupy just a cell. A problem can occur when the point is placed on the boundary of more than one cell. In this case, a rule should be formulated, e.g. doubtful points are placed in the cell immediately above or to the right of the border.
Linear geometry
The situation is not so straightforward for allocating linear geometry to grid cells, since lines can frequently cross cell boundaries. One solution to this problem is to cut the line at the cell boundary and to store the resulting boundary point twice, in both of the cells that share the boundary. This is not in general a satisfactory solution, as it tends to degrade the quality of the data by introducing points that ought to be collinear but are not, due to numerical imprecision of the computer. If linear and polygonal data are not cut at cell boundaries in a regular grid, the data stored in the cells may be references (or pointers) to the storage location of the complete geometric objects (Jones 1997).
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