Abstract Data-parallel algorithms for R-trees, a common spatial data structure are presented, in the domain of planar line segment data e.g., Bureau of the Census TIGER Line les. Parallel algorithms for both building the data-parallel R-tree, as well as determining the closed polygons formed by the line segments, are described and implemented using the SAM Scan-AndMonotonic-mapping model of parallel computation on the hypercube architecture of the Connection Machine. 							
						
							
					 															
					Erik G. Hoel, Hanan Samet