diff --git a/src/raster/r.accumulate/r.accumulate.html b/src/raster/r.accumulate/r.accumulate.html index 1711237c98..fe847d9c43 100644 --- a/src/raster/r.accumulate/r.accumulate.html +++ b/src/raster/r.accumulate/r.accumulate.html @@ -1,7 +1,7 @@

DESCRIPTION

r.accumulate calculates weighted flow accumulation, subwatersheds, -stream networks, and longest flow paths using a flow direction map. +stream networks, and longest flow paths (Cho 2020) using a flow direction map.

NOTES

@@ -62,12 +62,12 @@

Longest flow path calculation

With longest_flow_path option, the module will create a longest flow path vector map for outlet points specified by coordinates and/or -outlet with outlet_layer option. By default, longest flow paths -will be created as if there were subwatersheds at the outlets by calculating -the subaccumulation map. Downstream longest flow paths will never traverse -through upstream outlets. With -a flag, longest flow paths will be -created in an accumulated manner resulting in an overlap between downstream and -upstream longest flow paths. +outlet with outlet_layer option, using the algorithm by Cho +(2020). By default, longest flow paths will be created as if there were +subwatersheds at the outlets by calculating the subaccumulation map. Downstream +longest flow paths will never traverse through upstream outlets. With -a +flag, longest flow paths will be created in an accumulated manner resulting in +an overlap between downstream and upstream longest flow paths.

You can assign unique IDs to longest flow paths using id (with coordinates) and/or outlet_id_column (with outlet). @@ -100,17 +100,17 @@

Flow accumulation

r.colors map=flow_accum_new raster=flow_accum # check difference between flow_accum and flow_accum_new -r.mapcalc expression="accum_diff=if(flow_accum-flow_accum_new, flow_accum-flow_accum_new, null())" +r.mapcalc expression="flow_accum_diff=if(flow_accum-flow_accum_new, flow_accum-flow_accum_new, null())" -

For some reason, there are slight differences between the two output maps. -The yellow and purple cells show the difference raster map (accum_diff). -The red arrows and numbers represent drainage directions -(drain_directions) and flow accumulation by r.watershed -(flow_accum), respectively. Note that some cells close to headwater -cells are assigned 1 even though they are located downstream of other cells. +

There are slight differences between the two output maps. The yellow and +purple cells show the difference raster map (flow_accum_diff). The red +arrows and numbers represent drainage directions (drain_directions) and +flow accumulation by r.watershed (flow_accum), respectively. +Note that some cells close to headwater cells are assigned 1 even though they +are located downstream of other cells.