Grayscales

[Denholm]

Well, I'm giving terrain editing a shot, again. I'm hoping Blender doesn't give me a lot of trouble, as it always has something to gripe about.

Anyways, I had a few questions regarding grayscales. I managed to find some elevation maps using NOAA and another association I can't rcall at the moment. The problem is that the grayscale generated with the data isn't very high quality. So, firstly, what do you think?



Next, am I correct in assuming all grayscales have to be at a resolution of 1024 x 1024? I seem to recall NHawk giving me that information, I just wanted to confirm my suspicion. And lastly, how should I save this in Photoshop? I selected the image mode of, "Grayscale" then saved it as an 8-bit image. However, I just don't think that's right.

Thanks in advance.

[NHawk]

http://bbs.hitechcreations.com/wiki/index.php/Elevations_and_Terrain_Types#Using_Grayscale_Elevations

Yes, all elevation files are 1024 x 1024

In Photoship, click on Image, then Mode, then select Grayscale. Be sure the 8-bits/channel is also checked in that same menu.

From what I can see in the image you provided, you'll also have to adjust levels with Image, Mode, Adjust, Levels. Otherwise you'll have a steep drop off on your shores.

Also be carefull with elevations created by some web sites. They tend to include lighting which really messes things up.

[Denholm]

Yes, I noticed that. I made sure this one did not include light details. I'll give this one another touch up, then I'll use with it a while later.

EDIT: Since this is my first time playing with level adjustments, which levels would I be adjusting? Input or Output? How would I want to adjust them? Here's what I have (updated):

[NHawk]

The other option with the shores is to use the blur tool in Photoshop.

[Denholm]

Yeah, I started off with that. Don't really want to go back.

[mrmidi]

I can tell you from first hand experince that the above image tho the detail looks great,
is going to have some extreme elevation changes, as in the whites you have are going to be sheer cliffs down to 0 elevation.

I took the same image (below) and adjusted the levels, it will have the same detail but the cliffs won't be steep drop offs if that makes any sense. LOL




midi

[Denholm]

Well, I was hoping to keep the heavy terrain detail in there. It seems the darkness of this one almost eliminated that chance. Plus now the maximum elevation will be whacked off as I believe max elevation is set at white or 255. Perhaps I will have to go back to.... blur.

[Swatch]

keep in mind each color corresponds to a change in height, so if your max terrain height is 10,000 ft (a reasonable ski mountain peak), each color change = 40 ft  This means that if you go from a value of 0,0,0 to 15,15,15 (which still looks dark as all hell) you've made a transition of 500 feet... and that's an impressive mountain from ground level.  That's why that image seems so dark.  If there is a way to do false color (uses a varying hue instead of lightness) then it will help visualize this.

[Denholm]

Well yes, I am aware of how the elevation engine works. I was mentioning that it throws off the height because if I now input that maximum height is 10,000 it will, as you said, only place the maximum terrain at a height of half that (if not less) since the maximum elevation is not depicted in white (255).

Yes, I know I don't have to use that grayscale. Perhaps what I'm truly after is some tips on how to make a smooth transition to water without making the island larger than its actual size. I really dread having to use the blur tool as I seem to overdo it.

[NHawk]

Something you need to keep in mind is scale. I'm not sure which island that is (sure does look like Sicily), but remember that whatever size it actually is it's now being squeezed into less than a 64 square mile area. So, you are going to lose and/or distort detail.

If that is actually Sicily it is, give or take a few miles, about 150 miles long. To come near to duplicating the detail you would need to at least double the size of the island in your grayscale.

If the terrain grayscale is available with underwater information for the area surrounding the island your job would be much easier. You would simply eliminate everything that is below the level of the shoreline and adjust the levels to 1 to 255 (or 1 to whatever you wish). That would give you your transition to water without steep dropoffs except in the areas that actually have them.

[NHawk]

Something else that needs to be mentioned about using real life terrains...

There is a very real drawback to terrains in AH, and that's the inability to place land (or anything else) below sea level. So, any area on a real life terrain that is below sea level needs to be brought to 1 altitude so it remains as land. That can and does spoil the terrain detail in many parts of the world.

The other thing that can be done is to elevate the terrain to expose the details that are normally below sea level in AH. But, you are also then exposing what would not be visible below sea level on other parts of the terrain. It's a designer's judgement call.

[Denholm]

Okay, I finally found a decent elevation map of Sicily. Here's what I have now (Malta is displaced, just included to give perspective. Yes, I know it's too bright):



It's hard to see unless you zoom in. However there's a faint amount of gray (not black) at the shorelines where there seems to be a sudden drop. I think I'll just end up making a guess as to the location of Malta and simply place a few miles of flat terrain in its place (as I did with my last Malta terrain).

[NHawk]

I hate to tell you this, but that elevation map is satellite angle affected. Also, be careful you have stray matter in the elevation file. The image below is with black removed...

[RTHolmes]

I have the Mountain High series maps and wanted to use the elevation to do a terrain for Scapa Flow and the Isles. Turns out the "elevation" maps are side-lit and hence competely useless

[Denholm]

Yeah, I was looking for that, "dark-matter." I knew it was there somewhere.

Man, it sure is a shame there aren't any decent height-maps of Sicily (not affected by the angle of the satellite). Malta is fine remaining flat, as it doesn't have much elevation. But Sicily... That would be like ripping away the curtains while the girlfriend is showering.