[Award Winner] Using GIMP to Create an Artistic Regional RPG Map

[Aidan]

I got the Gimp a few days ago and have been trying to use it to create a map for a campaign I'm working on, and this tutorial is exactly why I came to the Cartographer's Guild. The results I've seen are amazing.

I have run into a problem near the very beginning though. I get as far as creating the land noise layer using the filters->render->clouds->solid noise.
I then set the mode of that layer to overlay...and nothing happens. It doesn't seem to do anything at all to the image. Am I missing a step here?

PS: I'm using Gimp 2.6.6 on Windows XP.

[Karro]

What layers do you have under the cloudy overlay layer? Are they all visible?

Basically, the Overlay feature just lays your layer on top of the layers below it, so that where your overlay layer is dark, it darkens the layer below, and where it is light, it lightens the layer below.

[Aidan]

Okay, I got past that problem. I was using a lower blur on my landmasses, because I had a fairly detailed coastline. The noise layer was just having a very small effect. I'm probably using this technique on a scale it's not meant for.

I'm pretty pleased with the results so far, but have bogged down at the rivers stage now. When I draw lines in black on the grass mask, it makes the rivers almost white, the lightest water color, which is the color from the layer that I used for the shorelines.

I'd attach my xcf file, but even zipped it's over 7 meg. Here's a jpg of the results though.

[Karro]

Okay, I got past that problem. I was using a lower blur on my landmasses, because I had a fairly detailed coastline. The noise layer was just having a very small effect. I'm probably using this technique on a scale it's not meant for.

I'm pretty pleased with the results so far, but have bogged down at the rivers stage now. When I draw lines in black on the grass mask, it makes the rivers almost white, the lightest water color, which is the color from the layer that I used for the shorelines.

I'd attach my xcf file, but even zipped it's over 7 meg. Here's a jpg of the results though.

I had the same problem (with regards to the continent outline). There's a certain level of detail for which this technique will not produce satisfactoricaly fractalized-looking coasts. You have to be willing to sacrifice a lot to the blur to make it work.

With regards to the river, if I recall the way the tut works, you're basically masking out part of the land to expose the underlying water color, But since the color that lies directly below the continents is the almost-white shoreline color, your rivers will look almsot-white, too.

If I'm recalling correctly then here's one potential solution: with your land showing, and your rivers already masked out, add a new layer between your lowest land and your topmost ocean layer. On this new layer (call it river color, or something) with a thin soft brush set on an intermediate blue value paint along the lines of the rivers. Play with different brushes and different layer settings to get the blend with the shoreline blue-white layer looking right. (I suggest leaving both your land layers and ocean layers showing so you can see the effect of the work as you paint.)

[Aidan]

I had the same problem (with regards to the continent outline). There's a certain level of detail for which this technique will not produce satisfactoricaly fractalized-looking coasts. You have to be willing to sacrifice a lot to the blur to make it work.

With regards to the river, if I recall the way the tut works, you're basically masking out part of the land to expose the underlying water color, But since the color that lies directly below the continents is the almost-white shoreline color, your rivers will look almsot-white, too.

If I'm recalling correctly then here's one potential solution: with your land showing, and your rivers already masked out, add a new layer between your lowest land and your topmost ocean layer. On this new layer (call it river color, or something) with a thin soft brush set on an intermediate blue value paint along the lines of the rivers. Play with different brushes and different layer settings to get the blend with the shoreline blue-white layer looking right. (I suggest leaving both your land layers and ocean layers showing so you can see the effect of the work as you paint.)

Yeah, I think I did something similar to what you're suggesting. I simply made another layer between the shoreline and the grass layer and used some cloudy noise and a color gradient with a couple medium blue colors then masked it with the land mask, and voila, there's blue beneath it.

I used RobA's tapered path stroking script and got a nice river, now I'm trying to figure out how to use a bump map to make it look even better.

[Karro]

Yeah, I think I did something similar to what you're suggesting. I simply made another layer between the shoreline and the grass layer and used some cloudy noise and a color gradient with a couple medium blue colors then masked it with the land mask, and voila, there's blue beneath it.

I used RobA's tapered path stroking script and got a nice river, now I'm trying to figure out how to use a bump map to make it look even better.

To do this, what I've done is this (and YMMV):

I included my rivers on my land mask, so that the land mask shows both the outline of the land as well as the rivers. I took this and made a new layer out of it - that is I created a layer where everything that is water (including rivers and lakes) is black and everything that is land is white. I blurred this slightly (how much will depend on the size of your map) but between 2 and 10 pixels ought to be enough. Then, I created a new layer filled with 50% gray. On this layer, I rendered a bump-map with my black-and-white land/water layer as the source. I don't remember the exact settings, but fiddle with them until you get something decent in preview: it'll look like the rivers and the coast slope gradually into the water. Once you do that, set the gray bumpmap layer to Overlay, and voila!

[BlackMojo]

Hey Everybody,
I have a bit of a problem. After I use the magic wand to select the land in the beginning, and i put the "Land Mask" Layer on top of it, It is just white with the selection markers showing up through it. There is no black for the ocean. Its kind of hard to explain, so here's a screenie. Any help would be great!

ty, Blackmojo

[RobA]

@Karro - bingo! that is how to do it easiest!

@BlackMojo - the land mask isn't a layer, it is a layer with a mask (right click on the new layer and add a layer mask using the current selection option)... but not sure of the exact step...?

-Rob A>

[BlackMojo]

So let me get this straight... I invert the selection so that I have the white land selected in the "Land Clip" layer, then I press the New Layer button (and name that layer "Land Mask"), Fill the new layer with white, and then right click the layer icon to add a mask? What kind of mask should i do? there is a list when i right click.

[Aidan]

@ Blackmojo: You want to use the magic wand to select all the non-white parts, then you invert the selection then you save the selection to a channel. This will be your land mask.


@ karro: I guess I knew how to do it, it's just that layer masks are giving me a headache.

The only thing you can apply to a layer mask is a channel, and you can't really convert a layer into a channel, you can only convert a selection into a channel. And you can't copy a layer mask from one layer to another, so if I end up editing a layer mask and I have several layers that use that mask, I can't copy it to the other layers. It appears when you duplicate a layer, the layer mask is copied along with it, but that's the only way I know of to copy a layer mask.

What I ended up doing for the water is copy-pasting my grass layer mask (which is where my rivers and lake is), bluring it and using that as a bump map to apply to a 50% gray layer.

So here's a copy of my map as it is now.

Aeryth2.jpg

I'm not real happy with the border...I'll have to fiddle with it some more.