public Column<V> col(int gridX) {
		return doGetColumn(gridX);
	}
A class that holds row and column data for each vertex and edge.  

<P> This class will take in a {@link GridLocationMap}, which is comprised of grid index 
values, not layout space points.  Then, the grid values will be used to calculate 
offsets and size for each row and column. Each row has a y location and a height; each 
column has an x location and a width. The height and width are uniform in size across 
all rows and columns, based upon the tallest and widest vertex in the graph. 

@param <V> the vertex type
@param <E> the edge type
Ghidra/Framework/Graph/src/main/java/ghidra/graph/viewer/layout/LayoutLocationMap.java