Similar to GRID WATERSHED except that the output will be in the form of a catchment region coverage.  Each pour point will receive its own catchment region.



WATERSHED2 <dir_grid> <source_grid> <out_cover> <out_subclass>




<dir_grid> - the input flow direction grid.


This grid can be created using the GRID FLOWDIRECTION function.


<source_grid> - the input grid that identifies the pour points that are to define the watersheds.


Each non NODATA cell is considered a pour point.  The value of each pour point is assigned to the output region User-ID.


Pour points can be a single cell, or many cells, e.g. a stream segment.


<out_cover> - the name for the new polygon coverage that will contain the catchment region subclass.


<out_subclass> - the name for the catchment region subclass.





WATERSHED2 runs from the GRID module of ArcInfo.


The pour points in the <source_grid> should fall on flow lines defined in the <dir_grid>.  The GRID SNAPPOUR function can be used snap the pour points to flow lines.





Grid: &run netdistance usage

Usage: WATERSHED2 <dir_grid> <source_grid> <out_cover> <out_subclass>


1)  To calculate catchment regions above every segment in a stream coverage:


Grid: setwindow dem_grid

Grid: setcell dem_grid

Grid: stream_grid = linegrid(stream_cover)

Grid: dir_grid = flowdirection(dem_grid)

Grid: &run watershed2 dir_grid stream_grid catch_cover watershed