XMDF  2.2
2.4.4. Geometric Path Groups

A "Geometric Path" is a list of points (x,y,z) that are connected together to form a series of line segments in space. The path represents the motion of an object through space. Each entry in the path is associated with a time. Additional data values may be associated with each entry in the path as well. For example, this could include the velocity of the object at this point in time, or the size of the object at this point in time.

Generally, there will be many paths grouped (or computed) together. For a group of geometric paths, each path would be defined from a shared set of time values. This allows the data to be stored as one three dimensional array, and a series of two dimensional arrays. The three dimensional array includes the coordinates (x,y,z) for a point on a path in one direction, the point index in the second direction and the time values in the third direction. The two dimensional arrays include a value for each point on the path at each time

In addition, the geometric path group will support an optional spatial mapping object that includes spatial bins of the area covered by any path in the group. Each bin will contain a list of the paths that intersect that bin and the time ranges that path is inside the bin.

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Figure 4 Geometric Path Group Layout