How do you determine topographical heights in your maps

[vorropohaiah]

This question applies more to the more modern maps, rather than typical fantasy maps.

I'm working on an atlas for my world in a topographical style and I;'m having difficulty coming us with the heights for the different topographical layers.

To be honest, they're arbitrarily chosen at the moment, though when comparing the height level's I've chosen to real-world maps, they're way off - my topography gets steep far quicker. It seems as though most real-world maps don't use a linear progression to the heights, so heights get graduially steeper as you move up in topographical layers, with the first 3 layers (typically green) being a lot lower than the next 3.

Like I said, my heights are all arbitrary at the moment. Though I don't want to change the maps themselves, I'm fine with changing heights for each topographical level and spot heights into something more realistic.

Does anyone know of how (if) there is a system for determining these heights, or are they arbitrary depending on the map?

If it makes any difference my world is larger than earth and the highest peak is 31,000 ft (Everest is 29,029)

[waldronate]

The histogram of altitudes for Earth is somewhat arbitrary and shifts a bit over time as plates move about and oceans rise and fall. https://www.google.com/search?site=&...tion+histogram is a nice starting search to look at the current information. From the histogram, you get to see the effects of material strength and continental plates vs oceanic plates. The highest little bit is the mountains (not a lot) and the bottom little bit is oceanic trenches (even less) The rest falls into two broad categories: continental crust (the area around sea level) and oceanic curst (the part after the big dropoff from the continental curst).

I referenced the search page rather than individual elements because there are a number of interesting graphs that show up on that page, including a comparison of a Venus histogram with an Earth histogram. This comparison clearly shows the difference between two-hump Earth one one-hump Venus that results from tectonics on Earth vs. no tectonics on Venus.

Note that these histograms are for whole-world situations. For an individual map, the relative abundance individual altitudes will vary. A Himalayan map, for example, would have a very different distribution than a map of a similar area near the mouth of the Mississippi river.

[vorropohaiah]

Thanks for that! I'm noticing the curve for mountains is a lot steeper than coasts and continental shelves, so I'm guessing that would also translate to the topography levels - so one level of mountain elevation would represent more vertical height than a level of coastal elevation. at least that's the impression I;m getting from most maps I'm seeing. Sorry for the lack of terminology

[Pixie]

I had the same problem a while ago, as the altitude in my maps was rising too sharply as well. When compared to Perfect-Mother-Earth-Model, there was almost absence of lowlands. So I had to rearrange the levels. My solution, in trying to keep it simple, was to make a sort of in-between progression, neither linear or exponential. I'm writing from memory, but it's something like:
0-50-100-200-300-500-700-1000-1300-1700-2100-2600-3100... (every 2 levels, double the difference between levels)

Then I did a comparison with Earth, using a similar hypsometric tint (you might want to google this), and I posted it a while ago in on of my ongoing threads (on a rush now, don't have time to find it and link). Have a look..

[vorropohaiah]

I had the same problem a while ago, as the altitude in my maps was rising too sharply as well. When compared to Perfect-Mother-Earth-Model, there was almost absence of lowlands. So I had to rearrange the levels. My solution, in trying to keep it simple, was to make a sort of in-between progression, neither linear or exponential. I'm writing from memory, but it's something like:
0-50-100-200-300-500-700-1000-1300-1700-2100-2600-3100... (every 2 levels, double the difference between levels)

Then I did a comparison with Earth, using a similar hypsometric tint (you might want to google this), and I posted it a while ago in on of my ongoing threads (on a rush now, don't have time to find it and link). Have a look..

thanks! I settled for:
0 - 750 (750)
750 - 1,500 (1,500)
1,500 - 3,500 (2,000)
3,500 - 6,000 (2,500)
6,000 - 8,500 (2,500)
8,500 - 11,000 (2,500)
11,000 - 14,000 (3,000)
14,000 - 17,000 (3,000)
17,000 - 20,000 (3,000)
20,000 - 23,500 (3,500)
23,500 - 27,000 (3,500)
27,000 - 31,000 (4,000)
31,000 - 35,000 (4,000)

though I'm realizing that the divisions are too big at low elevations and not big enough at high altitudes. I was trying to come up with progressive scale though didn't manage. I like what you came up with for yours. I'll probably come up with something like that for mine, bit with a few more levels (highest elevation in my world is 31,000 - 32,000)

[Charerg]

This may be obvious, but it's probably worth noting that Pixie's scale uses the metric system . Other than that, it's woth keeping in mind that the average elevation of earth is something like 600-700 meters (or about 2000-2300 feet), if you discount glaciated areas. The official average elevation is about 800 m (ca. 2600 ft), but this includes Antarctica and Greenland (which have extremely high average elevations due to those glaciers). That is, if you're going for a planet that is roughly similar to earth.

[johnvanvliet]

the same maps as are on redit for remapping

as suggested use qgis , it uses gdal

you also have contour lines so these can be converted to a esri shapefile

from a esri *.shp this can be converted into a 3d mesh qgis or in Blender using the gis tools ( a plugin on github)

all you need is the Z axis in blender for a black and white heightmap

the earth



then a created map in blender





now this is NOT using the contour lines , but that can be done . However it will take time to do .

for something from contour lines that will have to wait till sat or sunday for an example

[ranger]

I do not know much on the numbers thing you guys are doing and whatnot. But here is a very real reason you see this.
Erosion
before you say thats taken into account...it is but isnt properly
erosion causes loose materials to be washed away before the hardened areas, as the flow levels out, sediment settles, this is not just with rivers, but winds will also let their dust etc fall and move, it kinda slumps. Think of it kinda like a rock, and pour sand over it, then add water and whatnot, you will see much steeper gradients around the rock or higher elevation things. In addition some rocks are more prone to erosion compared to others this will cause some areas to retain a elevation more, etc, along with vegetation that will also strengthen an area sometimes leveling out the terrain.
There are many reasons for earth terrain to be how it is, in some areas you see steep gradient modifiers and vise versa. It all depends on what you want your world to look like, the arbitrary aspect and making it look like you want within realism (if you like realism)

[ranger]

if your talking about elevations and colors....if there is a map that does not have proper contour intervals they are doing it wrong....

[vorropohaiah]

I do not know much on the numbers thing you guys are doing and whatnot. But here is a very real reason you see this.
Erosion
before you say thats taken into account...it is but isnt properly
erosion causes loose materials to be washed away before the hardened areas, as the flow levels out, sediment settles, this is not just with rivers, but winds will also let their dust etc fall and move, it kinda slumps. Think of it kinda like a rock, and pour sand over it, then add water and whatnot, you will see much steeper gradients around the rock or higher elevation things. In addition some rocks are more prone to erosion compared to others this will cause some areas to retain a elevation more, etc, along with vegetation that will also strengthen an area sometimes leveling out the terrain.
There are many reasons for earth terrain to be how it is, in some areas you see steep gradient modifiers and vise versa. It all depends on what you want your world to look like, the arbitrary aspect and making it look like you want within realism (if you like realism)

thanks though I think i might have been too vague in my question. What I meant was: what determines the numbers, or distances, in the below key. Is there a universal system that assumes the distance between height A and height B need to be x, or is it arbitrary, depending on the cartographer and the type of map s/he's trying to represent. I'm beginning to think it's the latter, though there is a pattern between maps with lower elevations represented being shallower and higher ones being steeper, as Pixie mentioned

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