The edit subcatchment outlet pixels menu option allows for manual and visual editing of outlet pixels for a subcatchment. It also allows selected outlet pixels to be extracted and used to form new subcatchment outlets.
The Edit Subcatchment Outlet form can be accessed from this menu option (and then left clicking on a highlighted subcatchment) or by clicking the Outlet Details button on the Subcatchment Manager dialog.
This form presents a tabular display of the outlet pixels that form the outlet for the selected subcatchment. A new outlet pixel can be added by clicking the New Outlet Pixel and then typing in the row and column numbers. Outlet pixels can be deleted by selecting a row and clicking Delete Outlet Pixel.
Editing Outlet Pixels Visually
Outlet pixels may also be edited visually over the mapping layers by clicking Edit Pixels On DEM. This will cause the form to disappear, the outlet pixels layer (of the View Attributes form) will also disappear and only outlet pixels for the selected subcatchment will be shown in conjunction with other selected mapping layers. At this point you may manually click on DEM pixels to toggle their status as a member of the set of outlet pixels. With each click they will change to a red pixel or back again as shown below.
When you are finished, click Finished to return to the Edit Subcatchment Outlet form. The resulting changes will be automatically updated into the tabular display.
Subdividing Existing Outlet to Create New Subcatchment Outlets
Pixels for any subcatchment outlet can be selected and extracted to form a new subcatchment outlet. The outlets pixels that are used to create the new outlet can be selected by:
•Selecting rows in the outlet pixel table using either the 'Ctrl' or 'Shift' keys; or
•Clicking the Group Select By Polygon and drawing a polygon around the pixels (left click to create polygon vertexes and right click to terminate the polygon).
Once the required outlet pixels are selected, click the New Outlet with Selected and the selected pixels will be extracted from the current outlet and added as a new outlet.
