[Award Winner] Inkscape Tapering River How-To

[RobA]

Here is a real quick way to make nice, tapering rivers in Inkscape. I'm not sure what version I have (I always use the nightly windows unstable builds) but this require Live Path Extensions which are available in the last stable release.

Alternately, you could use the Path along path extension to get a similar effect, but not editable.

Start by drawing a long, horizontal taper. This will be your "pattern". The width a the right-hand size will be the width of the river mouth. My lines here aren't straight, they have a slight curve on them. select this and hit ctrl-c (or edit->copy):
2008-06-24_124823.png

Now draw the river you want. Start at the origin of the river and end at the mouth!. I use the pencil tool, then simplify the shape using ctrl-l (path->simplify). I then use the edit path by modes tool, select all the nodes (ctrl-a), and click the "make selected nodes smooth". here you can see the curce I drew with smooth node handles:
2008-06-24_124908.png

With the river curve selected, open the Path Effects dialog (path->path effects). From the "Apply new Effect" dropdown, pick "Pattern along Path" then click "Add". Click the clipboard icon to paste the pattern we had copied back in the first step on to the path. For rivers, select Single, stretched. You can click on the Node Edit tool in the path effect dialog, and you will be able to change the pattern dynamically, seeing how it looks on the path:
2008-06-24_125037.png

The nice thing about pattern along path is that the original path (the river) can still be edited, and the pattern will just follow.

Draw a tributary (again with the pencil tool, then simplify and smooth nodes), keeping the direction in mind again. Repeat the last step. Here I am editing the pattern nodes to make this segment more narrow:
2008-06-24_125530.png

To combine the rivers, select them all, and set their path and fill to "None", then group them together. Set the group fill to the colour you want (I picked cyan to demonstrate). Duplicate that group, and set the duplicate's stroke to a darker colour. I used blue, and 3 pixels. Now push the duplicate group below, and the whole river is nicely outlined (you could also blur the outline for a softer look):
2008-06-24_125806.png

It is just as easy to add lake shapes to the group before setting the group stroke and fill to make lakes and rivers with continuous shoreline strokes.

-Rob A>

[jfrazierjr]

Here is a real quick way to make nice, tapering rivers in Inkscape. I'm not sure what version I have (I always use the nightly windows unstable builds) but this require Live Path Extensions which are available in the last stable release.

Alternately, you could use the Path along path extension to get a similar effect, but not editable.

Start by drawing a long, horizontal taper. This will be your "pattern". The width a the right-hand size will be the width of the river mouth. My lines here aren't straight, they have a slight curve on them. select this and hit ctrl-c (or edit->copy):
2008-06-24_124823.png

Now draw the river you want. Start at the origin of the river and end at the mouth!. I use the pencil tool, then simplify the shape using ctrl-l (path->simplify). I then use the edit path by modes tool, select all the nodes (ctrl-a), and click the "make selected nodes smooth". here you can see the curce I drew with smooth node handles:
2008-06-24_124908.png

With the river curve selected, open the Path Effects dialog (path->path effects). From the "Apply new Effect" dropdown, pick "Pattern along Path" then click "Add". Click the clipboard icon to paste the pattern we had copied back in the first step on to the path. For rivers, select Single, stretched. You can click on the Node Edit tool in the path effect dialog, and you will be able to change the pattern dynamically, seeing how it looks on the path:
2008-06-24_125037.png

The nice thing about pattern along path is that the original path (the river) can still be edited, and the pattern will just follow.

Draw a tributary (again with the pencil tool, then simplify and smooth nodes), keeping the direction in mind again. Repeat the last step. Here I am editing the pattern nodes to make this segment more narrow:
2008-06-24_125530.png

To combine the rivers, select them all, and set their path and fill to "None", then group them together. Set the group fill to the colour you want (I picked cyan to demonstrate). Duplicate that group, and set the duplicate's stroke to a darker colour. I used blue, and 3 pixels. Now push the duplicate group below, and the whole river is nicely outlined (you could also blur the outline for a softer look):
2008-06-24_125806.png

It is just as easy to add lake shapes to the group before setting the group stroke and fill to make lakes and rivers with continuous shoreline strokes.

-Rob A>

Thanks Rob. I will eventually have to start playing with Inkscape. Again, I now owe you like 15 rep points...

CT's, give this many his 5th, umm 8th, 12th... umm I lost count... tutorial icon.

Joe

[su_liam]

Apparently I can't rep you yet. This one definitely earns it.

One modification I've found is, once you have the geometry to your liking, Convert Object to Path on your tributary river and then Union the result to the rest of your river system. It lacks the easy fixability of your way, but seems simpler, and, in my opinion, looks slightly better. You can then manipulate individual nodes on your uber-Path river.

[Karro]

So... can you import an image into the background of Inkscape so you can be sure you're placing rivers right?

Say... flatten a current copy of your working map and export it at (presumably at full size), then import into the background of Inkscape, get your river paths just right, then zap the background.

Then somehow, going back to, say, GIMP, import the river path right into GIMP?

I don't suppose you could detail the process you use?

[jfrazierjr]

This will be so much help to anyone who does not have a pressure sensitive tablet to be able to "fairly" easily draw rivers with a nice taper from start to finish.

Joe

[Karro]

This will be so much help to anyone who does not have a pressure sensitive tablet to be able to "fairly" easily draw rivers with a nice taper from start to finish.

Joe

Like me

[RobA]

Just an update -

There are some nice features being previewed for the .47 release of Inkscape. Worth mentioning in this thread are "spiro curves" and freehand shapes (kind of like stroke brushes). Here is a post with a video demoing these. Should make tapered rivers trivial in Inkscape (and spiro curves seem way easier than beziers for making rivers...)

-Rob A>

[RobA]

OK - Here is a real embarrassing update...

I discovered I had recorded a video tutorial (last fall) showing how to do this, along with my workflow of gimp->inkscape->gimp but never uploaded it

It is now hosted at ShowMeDo, so head over and give it a watch if interested! At the least it is another opportunity to laugh at my Canadian accent

http://showmedo.com/videos/video?name=2620020

-Rob A>

[Black Tower of Time]

OK - Here is a real embarrassing update...

I discovered I had recorded a video tutorial (last fall) showing how to do this, a
-Rob A>

Very nice tutorial. I hope to find more like those in the next time here :-)
Also the Mountain tutorial one you done saved nearly my live ;-) (never got the idea using the form-fill tool)
You ever tried the Fractalize methode / script in Inkscape to make river winds or maybe mountain range outlines ? I played around with it for coast outlines and like it so far.

[Vandy]

Hi, All.

Here is RobA's great tutorial as a PDF document.

Regards,

Gary

How to Taper Rivers in Inkscape.pdf