View Full Version : Making a river channel in gimp

04-26-2013, 09:15 PM
Is there a trick to selecting my rivers in gimp? In my heightmap the rivers came out just a few shades darker then the land and the color tool wants to select them and everything else.

Is there some other way to select them? I just don't want to paint over them when i color the land.

04-26-2013, 09:36 PM
There is an adjustment if you use "Fuzzy Select" you can play with the "Threshold" slider.

Still, you will probably need to use the Shift & Control keys to handle errors. <-- those allow you to add to a selection or delete from it.

04-26-2013, 09:50 PM
I never knew about the Shift/control keys. That will help i think, before i could get a little bit of the rivers but not much then one more click it would grab my coast and everything else. I will give that a try, i bump mapped it so its not like the rivers wont show when i color it but i would like to make them blue rather then green lol.

Thanks for the tip

04-27-2013, 01:54 AM
Well, something I've done many a time is once you do get it all selected (have all the marching ants where you want them) make sure you 'save to channel' and name it Rivers or whatever. That way you can re-select them at any time thereafter and never have to go through the selection process again.

You can also combine using the shift/ctrl keys with using the Lasso tool which depending on the situation works well.

05-17-2013, 09:31 PM
you could also save out the rivers as a map in wilbur first, Texture-> OtherMaps-> River Flow . Pick black for all the river aspects and white for the background. then in gimp select the whilte and delete it (clear). Use this map as a selection mask for your heightmap. or fill the black in this layer with your favorite river shade. *shrugs* Waldronate goes into it here, http://www.cartographersguild.com/tutorials-how/18280-award-winner-eriond-tutorial-gimp-wilbur-8.html post#74

05-18-2013, 12:06 AM
My piece of advice it to learn the utility of paths and masks. Sometimes I use the Selection to Path tool to keep handy a non-editable reference on borders and specific areas. You can always go back take this path and get a selection of the same area in one click. Masks sometimes help if they are a straight black and white and no gradients because you can easily select the opaque or transparent areas with the wand tool. Out of both tools I prefer having paths though, not as easy to edit and mess yourself up...