I would like to calculate catchment area. I used D8 algorithm and running in both arcgis 10.2 and SAGA GIS 2.1.2. However, the results from two software are different. The lowest value of catchment area in arcgis = 0; high value = 109325, while SAGA GIS lowest value= 625, highest value=47820. I think the result should be similar and maybe I do something wrong. Could you please explain what I did wrong? These are what i am doing,
the input: DEM25 In arcgis, to calculate catchment area: Dem25, then run tool flow direction, then run tool flow accumulation, then 25 (cell size) * 25 * flow accumulation
In SAGA GIS, terrain analysis -- hydrology --catchment area (parallel), elevation = dem25, sink routes=no set, weight = not set, catchment area = create, Step =1, linear flow = no tick, linear flow threshold =500. convergence = 1.100000001
Thanks so much for your help.