Land and water RGB values

[ReshiramLover 50]

When dealing with a grayscale image, 8-bit,. what is the darkest RGB value that is still buildable land and what is the lightest water value? Like if I wanted to create a flat region with some water.

 

Various websites give all kinds of values for these, no two websites tell the same values, but none are correct. They end up being all land or all water despite that these websites claim that RGB value x is water and RGB value y is land.

 

For example one websites says RGB value for land is 88 and water 85 meaning that all three RGB values are 88 and water 85. but when I load an image to both Terraformer and SimCity 4 itself (ctrl alt shift r), it ends up being all water. This website was incorrect.

Another website claims that the values are 83 for water and 84 for land but that is still all water in both the game itself and terraformer.

 

I don't have any height mod or anything, so I don't know why that the values of these websites are not generating terrain like claimed.

 

There has to be a different value that is correct for land and water, but I seem to cannot figure it out. These websites seem to be incorrect.

 

What are the RGB values I need to use for land and water for creating maps? Thanks

[CorinaMarie 29,894]

Thanks for posting this in the exactly correct forum of the Mapping Community Room. This area has so few viewers that I'm going to move it over to the SimCity 4 General Discussion forum where more peeps will see it.  

So, I did a test by creating a grayscale in Windoze BMP format:

Each of those bands are 32 pixels tall and the numbers correspond to the RGB value I gave them. Here's what it looks like after rendering in the game:

 

I did a single large tile with an all blue 4 x4 pixel config.bmp and the grayscale is 257 x 257 pixels in 8 bit format. I'll attach those two files to this post if you want to render this (using Shift+Ctrl+Alt+R in the region screen) and see what happens for you.

 

Height Test.zip

[jeffryfisher 2,176]

6 hours ago, ReshiramLover said:

a grayscale image, 8-bit,. what is the darkest RGB value

"8-bit" and "RGB" don't look like they go together. In an 8-bit grayscale image, each pixel has only one brightness value 0-255. To have RGB, you would have 3 values at each pixel (e.g. 24-bit RGB, usually written as a 6-digit hexadecimal code).

I recommend that you begin by checking your file format type and converting to real 8-bit grayscale if you're not there already. Only then can you start talking about numbers, and there won't be any 'R', 'G' or 'B' about them.

[CorinaMarie 29,894]

18 minutes ago, jeffryfisher said:

... there won't be any 'R', 'G' or 'B' about them.

I disagree with this. By making red, green, and blue all the same value that gives a grayscale "color" in my image editing software.

[rsc204 21,866]

Both systems rely on using the R, G and B values together to generate each shade of grey. The key difference is that 24-bit RGB can handle many more shades of grey than 8-bit RGB, in a similar way to how with colour images a higher bit-depth allows for more possible colours.

[ReshiramLover 50]

The grayscale image you posted is broken according to Windows and SimCity 4 won't read it.

[CorinaMarie 29,894]

2 hours ago, ReshiramLover said:

The grayscale image you posted is broken according to Windows and SimCity 4 won't read it.

Are you referring to the one in the attached zip file? The one showing in my post up there has been converted to a .png by Photobucket so saving from the posted image prolly won't work. Maybe someone else could download my attachment and try it to see if anything got messed up in the transfer. Otherwise, it is the exact grayscale from which I rendered the region.

[rsc204 21,866]

Just now, CorinaMarie said:

Maybe someone else could download my attachment and try it to see if anything got messed up in the transfer. Otherwise, it is the exact grayscale from which I rendered the region.

I just did, there is nothing wrong with the files inside the .zip.

[ReshiramLover 50]

Wait? There's a zip? I only see the two images where I right-click save as

[SimCoug 5,976]

1 hour ago, ReshiramLover said:

Wait? There's a zip? I only see the two images where I right-click save as

It's pretty obvious that it's at the end of CorinaMarie's post... but in case you missed it, here it is again.

Height Test.zip

[ReshiramLover 50]

Yours works but mine with 84 and 85 does not.

 

Mine using 84 for the land and 85 for the lake generates this:

 

I used this:

My Height Test.bmp

 

and here is the zip

My Height Test.zip

 

 

It works fine on yours but makes all water with the same 84 on mine.

 

That is messed up.

 

Anybody know what the problem could be?

[CorinaMarie 29,894]

50 minutes ago, ReshiramLover said:

That is messed up.

Yeah, I agree.

So, I checked your files and Window's properties says they are 8 bit and GIMP says they are grayscale. I render in the game and get all water. Weird. But then I simply exported your file to a new name without having changed anything at all and then it renders as land in the game just as we want.

That narrows it down, I believe, to something in the way your program saves the file. Like maybe it's adding an alpha channel or not adding one or something. (I'm confuzzled and just guessing now.)

[jeffryfisher 2,176]

On 6/3/2017 at 10:24 AM, CorinaMarie said:

By making red, green, and blue all the same value that gives a grayscale "color"

You're not thinking like a computer. Grayscale for mapping is not about producing color, it's about providing one byte of height data at each coordinate. We as map developers are sort of cheating by using paint and other graphics programs to draw colors (shades of gray) to represent heights.

Now, it might be possible for a program like SC4 or some external terraformer to convert 24-bit color into 8-bit gray to produce a height data file, but I wouldn't count on it. Knowing what I do about computer science, I'll always do the conversion myself so that I give the program exactly what it needs: an array of height data bytes.

On 6/3/2017 at 0:47 PM, rsc204 said:

Both systems rely on using the R, G and B values together to generate each shade of grey

No, that's not correct. 8-bit grayscale has no R, G, or B. It has only brightness 0..255 from black to white, which is what makes it so useful for producing a map of height 0-255 values. Your monitor might display each pixel using a cluster of R, G & B phosphors, but that's completely irrelevant to the data file, and it's the data file needed to provide elevation data points for a map.

On 6/3/2017 at 0:47 PM, rsc204 said:

24-bit RGB can handle many more shades of grey than 8-bit RGB

That's a non-sequitur. I don't think there is such a thing as 8-RGB (8-bit color uses lookup-table, aka "palette"). 24-bit RGB has exactly as many shades of gray as 8-bit grayscale. The difference is that 24-bit RGB wastes data space because it only uses a fraction of its possible values when displaying only its gray (R = G = B) values.

SimCity 4 uses only heights from zero to 255. There can only be 256 possible heights, so having more possible values would be wasted even if they were possible. SC4's height data is the same data structure as 8-bit grayscale (brightness). Nothing else matters.

If you want to make a map for SC4, then stop thinking of it as a graphical file and start thinking of it as a height data file being sneakily displayed in a paint program as something that it's not. In other words, at the end of the editing, respect the program's data structure needs so that it will produce the map that you want. If you insist on making the program swallow your graphics of choice, then don't be surprised if it has indigestion.

[ReshiramLover 50]

I used the save as in Photoshop. so Photoshop is doing something to it.

[ReshiramLover 50]

I tried opening the bmp in Gimp and exporting immediately without changing and it is STILL NOT WORKING! there is supposed to be a stomach shaped lake but all I get is this:

 

This is NOT what it is supposed to look like.

 

Opening this in Gimp and exporting does not work for me

 

Anybody know what the problem could be?

 

[CorinaMarie 29,894]

1 minute ago, ReshiramLover said:

Anybody know what the problem could be?

Attach your latest grayscale and I'll see if it renders for me.

[ReshiramLover 50]

My Height Test.bmp

[CorinaMarie 29,894]

It renders all land for me. Checking the grayscale pixel values I find some at 85 and some at 84. Both of those are above sea level. Try 82 or 83 for your lake.

[rsc204 21,866]

28 minutes ago, jeffryfisher said:

No, that's not correct. 8-bit grayscale has no R, G, or B.

You are right to say that data isn't going to be in the save file, but you can use RGB to generate greyscale colours during creation. A lot of this depends on the applications you use and your workflow.

31 minutes ago, jeffryfisher said:

That's a non-sequitur. I don't think there is such a thing as 8-RGB (8-bit color uses lookup-table, aka "palette"). 24-bit RGB has exactly as many shades of gray as 8-bit grayscale.

Here I've been a little stupid and mixed things up when talking about image formats. We went from 256 colours straight to 16-bit colour on most computer systems. But the general point I was trying to convey, was simply that a higher bit-depth means more colours (even if those are shades of grey), to choose between.

34 minutes ago, jeffryfisher said:

SimCity 4 uses only heights from zero to 255. There can only be 256 possible heights, so having more possible values would be wasted even if they were possible. SC4's height data is the same data structure as 8-bit grayscale (brightness). Nothing else matters.

However, you are perhaps missing a valid reason for using a higher bit-depth, which is for a better quality source image. Sure, eventually that will be converted to a format SC4 can work with. But utilising an application like Terraformer, I often find myself working with higher bit-depth images. I'm pretty sure the limitation of 8-bit only applies to the in-game renderer, thus rendering the region using another application, you can attain a higher quality result. So there are benefits to be had using a higher quality image. Straight from SC4TF readme:

"Export of full range ( 0-6000m ) elevation within 0.1m precision in SC4M format and 16bit greyscale png format and RGB format"

I believe that's vastly more than 256 possibilities.

[CorinaMarie 29,894]

To clarify, remember this one that rendered ok for you with water at the bottom and land to the north?

There are 8 bands of grayscale starting with 81 up to 88. Notice in the render that 81 to 83 are water and 84 to 88 are land.

[ReshiramLover 50]

Your screenshot shows 85 as below sea level as well as my rendering of your image

 

Nevermind, the 83 looks like an 85 in the image

[CorinaMarie 29,894]

1 minute ago, ReshiramLover said:

Your screenshot shows 85 as below sea level as well as my rendering of your image

Can you see the numbers in the grayscale? It's 81, 82, and 83 at the bottom that become water and then 84 up to 88 that are land. The rendered number 83 (in the water closest to the land) does look a little goofy, but you can see in the grayscale it's clearly an 83.

[Odainsaker 2,137]

3 hours ago, CorinaMarie said:

That narrows it down, I believe, to something in the way your program saves the file. Like maybe it's adding an alpha channel or not adding one or something. (I'm confuzzled and just guessing now.)

It is indeed something about the way ReshiramLover's files are being converted to grayscale and saved or the options he is choosing when he converts and saves.

@ReshiramLover's first My Height Test is not actually the 256-color grayscale image that we want.  Inspecting it with Paint Shop Pro and Adobe Photoshop reveals that it is actually an Indexed Color image.  The quirk with Indexed Color is that the image has a custom color palette containing only those unique color swatches that are used in that particular image rather than the full 256-color grayscale palette.  This is done to reduce file size, but it is not an ordered palette SimCity can correctly use.  Instead of a color being normally referred to as, say, "RGB 85," it is being called "I 2," or Indexed color 2 on the file's custom palette, pointing to a swatch that is RGB 85.  SimCity may be instead reading these in order, and incorrectly sees instead "RGB 2."  The second My Height Test, the one with the stomach-shaped lake, has a broader palette than the first, but its palette is still missing some of the expected 256 grayscale color swatches and has other swatches reserved or shifted.  Converting it to the proper grayscale image we want, a process which rekeys the indexed color palette to a 256-color grayscale palette, creates an image where the land is mostly at 64 with a stomach-shaped depression at 63, and we will need to repaint these to 84 and 83.

If we are using Adobe Photoshop, we want to be sure that our image is converted to grayscale using the top menu option:  Image-->Mode-->Grayscale

For those using Paint Shop Pro, use the top menu option:  Colors-->Grey Scale

I am not familiar enough with GIMP to offer the correct path.

 

  Edited June 5, 2017 by Odainsaker  

[ReshiramLover 50]

None of these are working. They only render water even with 83 and 84 and terraformer claims that it they are not a valid image files but nothing could be further from the truth! SimCity 4 reads it albeit only water and terraformer will NOT read it at all!!

Stomach 2.bmp

Stomach 1.bmp

Stomach.bmp

[ReshiramLover 50]

23 minutes ago, Odainsaker said:

@ReshiramLover

If we are using Adobe Photoshop, we want to be sure that our image is converted to grayscale using the top menu option:  Image-->Mode-->Grayscal

 

 

I have been doing this every time.

[APSMS 1,893]

Have you tried opening and resaving your images in the most inane of programs, Microsoft Paint?

That should strip out any fancy options if you resave your image as a Bitmap (.BMP), provided of course, that the color values are already at the aforementioned 83 and 84 Greyscale

[ReshiramLover 50]

17 minutes ago, APSMS said:

Have you tried opening and resaving your images in the most inane of programs, Microsoft Paint?

That should strip out any fancy options if you resave your image as a Bitmap (.BMP), provided of course, that the color values are already at the aforementioned 83 and 84 Greyscale

Still not working. All water. Same thing in Terraformer

 

Just admit it, the values given on all those websites and given to me on here are false. This is a wild goose chase

[Odainsaker 2,137]

1 hour ago, ReshiramLover said:

Stomach 2.bmp

Stomach 1.bmp

Stomach.bmp

These are still showing wonky color tables.  In Paint Shop Pro, a working grayscale should look like this:

where there is an even range of gray values from RGB 0 to RGB 255.  (My eyedropper color selection tool is not showing in the screen captures.)

 

However, yours are coming out as Indexed Colors like this:

where the highest value is only RGB 238, and the initial swatch is a brown RGB 82,71,66 (the little brown blip at the top left).  While it otherwise looks like an even gradient, there actually numerous duplicated swatches and missing grayscale values, leaving the remaining values shifted on the table.

(Sorry, I don't offhand know how to produce a similar table within Adobe Photoshop)

 

Your images' color tables are still getting messed up somewhere and turned into a truncated Indexed Color table, perhaps due to an option ticked while saving.  Perhaps, like previously mentioned, there is an alpha channel, layer, or floating selection in your original image before saving, or you have some sort of compression setting or other fancy trickery going on.  I can't reproduce the steps by which you get such a color table, but it is also the identical color table issue I can see in the second My Height Test file.

Using the freely available Adobe Photoshop CS2, I can convert the posted images to grayscale using Image-->Mode-->Grayscale and then save as BMP with only the BMP options "File Format:  Windows" and "Depth:  8 Bit" ticked, and the result is a correct grayscale image with the correct grayscale color table.  However, just getting the file's color table correct is only a first step.  When I do it with Stomach.bmp, I get a image that now has a corrected color table, but, as indexed color tables do not necessarily peg directly to corresponding 256 grayscale colors, the corrected "land" here will now be at RGB 44 and the "water" at RGB 43, which means both in SimCity will actually be well underwater.  This now underwater image with the corrected color table will actually still have to be further repainted, flood filled, brightened, or otherwise hands-on adjusted in some convenient way so that the "land" and "water" become RGB 84 and RGB 83 on the corrected table.  Of course, it all then again has to be saved without somehow also again inadvertently messing up the file's color table

[rsc204 21,866]

12 minutes ago, ReshiramLover said:

Just admit it, the values given on all those websites and given to me on here are false. This is a wild goose chase

Here's a thought... maybe you need to take a break, give yourself a moment to calm down and add some patience and clarity to the problem at hand. These values do work, when Corina gave you a file correctly formatted, the import was working just fine.

5 hours ago, ReshiramLover said:

Yours works but mine with 84 and 85 does not.

What does this tell us? In short, something that you are doing to your images is messing with the correct values.  Different imaging applications and formats all can do things differently, leading to unexpected results. This is a really complex area and if you don't configure these settings right, the image you save simply isn't going to work.

Anyhow, @Odainsaker has explained things better than I probably could (whilst I'm typing). It's worth noting that once your original image is formatted incorrectly, you may find it quicker to simply start over than try to fix the problem. However, before doing that, get a working test image so you don't waste lots of time to get the right settings for exporting the image. That way you won't have any problems with the final work second time around.

[cogeo 960]

Rendering a map with the image-import feature (Alt+Ctrl+Shift+R) uses 8-bit images, even with 24-bit RGB image files (the game uses only one of the three components, I think the green one - although one can experiment). In the maps I have uploaded I used 8-bit (grayscale) .BMP, so as to avoid .JPG's "lossy" compression.

As for the color values, the game uses the ImageImportScaleFactor property in the Terrain Properties exemplar, to calculate the resulting elevation for every pixel. The default value of this property is 3.0 (a so called Height Mod may override it). So a value of 83 results in an elevation of 83×3=249m, ie just below the (default) SeaLevel of 250m, while 84 becomes 84×3=252m. You can use the TerrainQuery cheat to check the exact elevations ingame. And @Odainsaker, yes, the game appears to use the palette index number, rather than the actual color value, so if you are using an "indexed" (or else "paletted") grayscale format, make sure that your palette includes all 256 shades of gray, and every palette index number corresponds to the same color value, eg palette entry 100 corresponds to the RGB value of (100,100, 100). Image-processing programs have options to "Optimize the Palette", this eliminates unused palette entries, and only saves some few bytes in the image file, but causes such problems, like renumbering palette indexes etc. You should disable any such option.

8-bit images have two big limitations. One is that it can represent only 256 discrete elevations, resulting in an ugly "steps" effect at gently-slopped areas. The other is the elevation range limit. The maximum elevation value is 255×3=765m, that is only 515m above sea level. One can make a Height Mod, to use a larger ImageImportScaleFactor, but then this exacerbates the steps effect. The .SC4M format (custom map format generated by SC4TF and usable by SC4M), and 16-bit PNGs use 16-bit encoding, which is double as wide, allowing for far greater range (up to some 6500m) and precision (steps of only 0.1m). You need to either use SC4TF or make an application capable of saving 16-bit PNGs, and use the SC4 Mapper to import your map, not the ingame image-import feature.