(help plz) Gimp Technique: Rivers to Sea-Level on Map_H - Printable Version

+- All-Aircraft-Simulations (https://allaircraftsimulations.com)
+-- Forum: IL2 MAP MODS Download & Discussion (https://allaircraftsimulations.com/forumdisplay.php?fid=269)
+--- Forum: OLD IL2 MAP MODS Discussion & WIP-MAP-MODS (https://allaircraftsimulations.com/forumdisplay.php?fid=307)
+--- Thread: (help plz) Gimp Technique: Rivers to Sea-Level on Map_H (/showthread.php?tid=58770)

---

(help plz) Gimp Technique: Rivers to Sea-Level on Map_H - Dixiecapt - 15.01.2009

sorry i haven't put together a WIP with pictures yet but im putting all my Free time into this Korea War Map.

What I'm doing now is cutting the rivers into Map_C, but I have learned I need to make sure those rivers are at Sea Level on Map_H for my Bridges.

I DID look before I asked, and I remember someone talking about a technique for accomplishing this by layering the images to trace the rivers on Map_H on Gimp.... I can't find, or figure out the best way to do this, I even tried to figure it out with my cool Geek Professor for my educational technology class.

Thanks for any tips or instructions you can give folks!!!

---

- lowfighter - 16.01.2009

I'm not sure it's the best way but:
1. open in gimp the full uncompressed water map let's say Mymap_c.tga. Select all regions with color around rgb=0 (water), copy (I think you need to have antialiasing unchecked)
2.open map_h.tga and paste
3. fill the layer with black RGB=0 (so the gray colors are all converted to black which means height 0)
3. go to layer and scale down 4 times in both dimensions, with "none" for the scaling method.(if the layer is say 400 by 200 pixels then you scale it to 100 by 50 pixels)
4 move the layer till you get the right position
5. anchor layer
6. save as with RLE compression unchecked

You may then still have problems which you have to correct manually but maybe Redwulf,s utility can do the job automatically...



To no 4.
If My map_c has water in the lower left corner then getting the right position is just moving the scaled layer till it's lowere left corner matches the lower left corner of the whole image (map_h)
And so on, you'll find the way

---

My way to do it - delvpier - 16.01.2009

I do it in Photoshop because I think it's better than Gimp for brushes size and others... but you can apply the principle with Gimp.

1/ make one copy of your map_c resized divided by 4, same as map_h

2/ open this copy and map_h, add a new blank layer to copy of map_c, copy map_h and paste on this new layer so you have map_c as background and map_h as foreground

3/ play with opacity of map_h layer so you can see rivers painted on background layer

4/ choose a brush (not stencil !) with a size a little bigger than river width, color black and paint over river as guide... try to keep center of brush right over river, it is important as you take a brush and not a stencil

5/ once finished, duplicate map_h layer and save as a new map_h.tga... and look result in game :wink:

All I said is working in Photoshop... in fact I think in Gimp you have to paste map_c copy as a layer over map_h (PSP paint on foreground layer when Gimp paint on background layer...)

When choosing brush size try to be realistic... enough to cover river width but small enough to keep real landscape :roll:

---

- Dixiecapt - 16.01.2009

Thanks both of you....

I can't find a way to lay the layers on top of one another in Gimp and being able to see both, they seem to just completely cover each other.

I think I got Lowfighters concept though, I Downsized a copy of Map_C, then cut the rivers, then used select by color to pick the water, copied it, pasted it on Map_H, and since black is ground level I THINK this should take care of it.

haven't tested it yet.

BTW thank's ya'll.




Yes I say Ya'll

---

- delvpier - 16.01.2009

For opacity in Gimp :



For me it's important to use brushes a little bigger than rivers width and not only placing black color on river... in one way, setting rivers at sea level in map_h is like cuting in relief... for low heights it is not really important... but for higher heights you have to cut softly with smooth transition between actual relief and color you paint...

As illustration from map above :wink: :roll:

Durance river in a real relief at 700m :



River in Corse, all length, start in relief at 1400m :



Both are at sea level and integrated smoothly in high relief...

Anyway, you can't follow sea level river into highest heights... differences are unrealistic...

---

Need some help with this please - Mission_bug - 23.08.2009

Forgive me for being dim but I can't seem to make this river thing work any way I try.

I take it map c and h need to be the same size and then you draw the lines onto c using h as a guide, or are you supposed to draw on each?

Gimp simply won't let me alter any of the images to the values necessary, it allows one dimension but puts its own in for the second, so you can't get both maps the same size!

How do you save just the one layer?

This is driving me crazy, is there a step by step tutorial available anywhere please?

Wishing you all the very best, Pete. :???:

---

Re: Need some help with this please - agracier - 24.08.2009

Mission_bug Wrote:Forgive me for being dim but I can't seem to make this river thing work any way I try.

I take it map c and h need to be the same size and then you draw the lines onto c using h as a guide, or are you supposed to draw on each?

Gimp simply won't let me alter any of the images to the values necessary, it allows one dimension but puts its own in for the second, so you can't get both maps the same size!

How do you save just the one layer?

I

---

Finally a river. - Mission_bug - 24.08.2009

Thanks agracier for the help this was doing my head in. Yourself and Kirby have very kindly sent me in the right direction, and here is the result.

This was the earlier attempt, I think I was drawing with too big a brush, not black but grey, not quite joined up.



Here is the second attempt, 1 pixel more defined, not quite there but closer me thinks



I went against the original information and used map h as a guide for the rivers because the water was easier to make out.

The above were a test, I now need to draw all the water courses, will probably take all day tomorow. Day Off.

Wishing you all the very best, Pete.

---

- agracier - 25.08.2009

The second attempt is indeed the right way to proceed, you do have the waterways at the right height and all ... but to get rid of the straight, geometric look that the river now has, you ought to blur my_mapC.tga after you have finished making/drawing the rivers on, but before you use the coast align tool.

Both GIMP and Paint Shop Pro and PS have blur tools. Sometimes you need to run the blur tool several times on my_mapC.tga to achieve a good natural look for coast lines and rivers ...

---

- Mission_bug - 25.08.2009

Thanks for that Agracier, I have been playing around with rivers again today and gave them a couple of shots of blur before merging the images.

It certainly improves the appearence.



I found I needed to use a pen at three pixals though because if I used one Pixal the rivers seemed to break up into smaller piecses, also the rivers look huge don't they, could do with some way of narrowing them and making streams.


Wishing you all the very best, Pete.

---

- agracier - 25.08.2009

The thing is with rivers, if you don

---

Just a question - farang65 - 06.09.2009

Hi There,

I can make sea level rivers and massive water basins in Gimp no problem and then use redwolf's aalign coast tool.

Just a question if you are making lakes and rivers which are not at sea level such as in mountainous zones do you use

RedWolf's coast align tool on these new areas or not?

Cheers Kirby

Lamphun

---

Re: Just a question - agracier - 07.09.2009

farang65 Wrote:Hi There,
I can make sea level rivers and massive water basins in Gimp no problem and then use redwolf's aalign coast tool.
Just a question if you are making lakes and rivers which are not at sea level such as in mountainous zones do you use
RedWolf's coast align tool on these new areas or not?
Lamphun

I

---

Re: Just a question - Redwulf__32 - 08.09.2009

agracier Wrote:[quote="farang65"]Hi There,
I can make sea level rivers and massive water basins in Gimp no problem and then use redwolf's aalign coast tool.
Just a question if you are making lakes and rivers which are not at sea level such as in mountainous zones do you use
RedWolf's coast align tool on these new areas or not?
Lamphun

I

---

- agracier - 08.09.2009

Just to clarify gents .... CoastAlign does NOT push inland water to sea level, this seems to be a common misunderstanding.
_____________________________________________________________________________________________________

Hmmm ... then I

---