Summing upstream lengths

• Using a recursive algorithm RivEX is able to sum all upstream polyline lengths and write it back for each polyline.  This sum length also includes the polyline itself.

• The output of the summing process is a single field in the attribute table of your river network called US_Accum.

• The image below demonstrates how RivEX deals with braided networks. Red numbers are the lengths of the polyline and black numbers are the accumulated lengths which would be written back to the file.