Why do the pour points shift?

[DaveSimpson]

I am using the online watershed tool to identify watersheds.  It works great, but my pour points are shifted from where I selected.  Why do the pour points shift, am I missing something?

[IanMurray]

Could you be a little more specific about what online tool you are using?  A link would be helpful....

[DaveSimpson]

Sorry, it is the arcgis on hydro.arcgis,com tool. See screenshot below. You can see the offset of the pour points in the lower left.

[SepheFox]

I'm guessing it's because you have the Return Snapped Pour Points box checked.

[SepheFox]

To be more specific, "The service will move points to be optimally located relative to the flows in the elevation model if they are not already there." You want the pour points to be on the nearest point of highest floe, or you will end up with tiny little watersheds.

[DanielStauning]

Dave,

I would explore the snap distance parameters in the tool, here is the documentation: It should snap to the cell of highest accumulated flow and move the pour point to that location.

Watershed—ArcGIS REST API: Elevation Analysis services | ArcGIS for Developers  

Thanks,

-Dan

[DaveSimpson · Accepted solution]

OK, I figured it out.  I used a snap distance of 30 which is the resolution of the data source I selected.