. A column named ‘nextID’ denoting the next downstream subbasin IDs is uploaded to the subbasin table which is then used to produce the SWIM routing (.fig) file. In addition, the module produces a routing network vector map, a mainstream vector and raster map, subbasin outlet and inlet point vector maps (all map have default output names or can be set) and it uploads an additional column to the subbasin table named ‘inletID’ mapping the subbasin to an appropriate inlet. The additional output is mainly useful for visualising the routing structure, while the mainstream raster map is needed for the subsequent Although the module can produce both the ‘nextID’ column and the SWIM routing file in one execution, the recommended work flow is to first produce the routing structure (from-to subbasin IDs) and the additional maps, then (visually) examine the results using the created flag set (see examples). If the subbasin map was produced with the same accumulation map and in the same resolution/region, then the routing structure is expected to be exact and reflecting the river network as shown in the map. The routing network vector visualises the routing and either just shows the connections between the outlets and inlets (default) or the lines from centroids to the outlet and inlet using the flag. Although the routing can be manually changed by either changing the subbasin IDs in the nextID column of the subbasin vector or by using the argument, it is recommended to make sure the same accumulation map was used to produce the subbasins or to ‘burn’ a more accurate river network into the DEM and then remake the accumulation map using r.watershed (!with the -s flag!). (in the same resolution and grass region)!!! If this condition is not met, inexact routing and multiple outlet subbasins are highly likely. Although this module has been tested, it is still in beta mode and hasn’t been extensively error coded. Please report unexplained errors to the author (see below). In addition to the subbasins vector and raster map, this also produces catchment raster and vector maps, accumulation, drainage, streams, slopesteepness and slopelength rasters (as needed by the subsequent m.swim.* modules) by default. Calculate the routing structure, routing network and mainstreams (the output defaults are: mainstreams=mainstreams, routingnet=routingnetwork, outlets=subbasinoutlets, inlets=subbasininlets, which can also be set explicitly): Source.