Identify Vertex Coordinates of Segment Endpoints

Identifies the vertex coordinates (row numbers) of the endpoints of a given segment. The main purpose is determining which of the endpoints is the mouth (or lowest point) of the river system.

showends(seg, rivers)

Arguments

seg	The segment (number) to check
rivers	The river network object to use

Note

This function is called within cleanup, which is recommended in most cases.

Examples

data(Gulk)

# say we know that segment 1 is the lowest segment in this river network, but we don't know 
# which end is the mouth.
showends(seg=1, rivers=Gulk)

# this means that the mouth is row 1, so we can specify this:
Gulk <- setmouth(seg=1, vert=1, rivers=Gulk)