This creates gaps and overlays between the two polygons. Point dictionary prevents duplication of points. It does this by labeling each point. It creates an array of numbers and in so doing decreasing the amount of data that must be stored. Arcs or lines would create the polygon.
Nodes are the end points of the arcs and the other points along the line are called shape points.
Shape points are less important points compared to nodes. The computer reconstructs the polygon by going back to these nodes and creating the arcs of lines. The raster data model is composed of a grid and each cell within the grid holds data. Another way to explain it is that the polygon has a grid laid over it and the polygon would fill those cells with data, each cell in the grid being assigned a value. In the raster format the attribute is directly in the raster grid.