What is a good professional approach to draw beautiful rivers on a map?

Question

I draw a map in Inkscape. Rivers on a professional map should begin with a thin long tip, then it changes line width little by little and in the lower reaches of a river may even become a polygonal figure with dark blue edge and blue fill. I can draw it completely by hand, by multiple sectors with different width and the last I will draw as a polygon bezier line. I will take some time, because I would have to correct nodes and set up widthes. May be there is an approach, that would allow me to set beginning and ending withes of a bezier line? I tried some Inscape operations that allow to set this, but width changes too quickly and the tip is too thin, it's very difficult to get something from this. I would like a quick way to draw professional carthography products with Inkscape. Very appreciate any help with this. UPD: Power Stroke gives the opposite -

Answer 1

Thanks to Billy Kerr. I realised the proper way to do it. My settings are: CubicBezierJohan, MeterLimit 4.5, Join Spiro. But I should pull a node near the end and near the start points, until I got desired width change.

Answer 2

Think this as your wanted river. It's an otherwise OK drawn Bezier curve, but it has a constant width like drawn paths generally have:

Think this three node horizontal triangle as the wanted width profile:

If you copy the triangle to the clipboard, give to the constant width river path effect "Pattern along Path" and let the triangle in the clipboard be the pattern, you get this:

It can be actually got already during you draw the path if you select shape option "Clipboard" for the Bezier tool.

You can remove the black outline by removing the stroke. To get a blue fill you simply select a blue fill color and you will get this:

It is still an editable single stroke path with a path effect. The effect can be removed if needed. Inkscape remembers the used pattern => you can take the used pattern back to canvas and edit it; the editing affects the resulted river. The details of the effect dialog fortunately are easy to understand.

You can convert the river to a strokeless closed shape by applying Path -> Object to Path. After it the river becomes a totally free object which can be used in path operations such as union and subtract. But turning it back to a single stroke curve is difficult (except by applying UNDO immediately), so it can be a good idea to have also a copy of the single stroke version in a hidden layer.