In the other thread, I computed manually an offset to center (approximatively) the whole map in the sketch. Then, drawing each state one by one with the same offset, they kept their relative offset with regard to the whole map. Which is useful...
So, each SVG shape has its own offset, which can be defined by a number of factors: which group, with various transformations, they belong to, the definition of the path itself (it is defined by coordinates within the coordinate system of the SVG), and so on.
So I fear you have to compute the offset of each sub-shape yourself. Once done, perhaps you can store them in an array.

Note that for a given shape, you have getVertexCount() giving the number of vertices, and getVertex(i) returns the float[] coordinates of the ith vertex. If you average these coordinates, you might get an approximate offset to apply on your shape. Worth trying, at least.