Export vertical flow flowlines (kcu = 150) with a modified geometry

[leendertvanwolfswinkel]

startpoint = Point(line.coords[0])
endpoint = Point(line.coords[-1])

start = translate(startpoint, xoff=1, yoff=1)   # +1 in x and y
end   = translate(endpoint, xoff=-1, yoff=-1) # -1 in x and y

line = LineString([start, end])