maps with large horizontal scale

[UncleBob]

Hello everyone, I happened over this nice programm yesterday and I'm playing around with it to see if I can use for my purposes.

First of all, sorry to the admins, I'm afraid I made a terrible mess when registering, managing to type in a wrong email address twice. You can delete the account "Jedidia", that was me messing up one of my addresses with the provider of another...

Anyways, here goes the problem: I'm in the process of designing a graphically rather oldschoolish fantasy RPG. Turn-based, tile graphics, all that stuff. It'll have a rather large scale and make heavy use of procedural content, but I wanted to make a standard world map, and I'm not too hot on fractals, so I thought a 3rd party aplication to generate the heightmap of my world would be the best way to go. I can handle the rest like temperature distributions, vegetation aso, I just need a solid heightmap to go on.

The world-map is supposed to be 2048x2048 tiles, with every tile representing 5x5 miles. Clever me though it should be easy to just produce a heightmap with some generator and take every pixel as a tile, so I'd get nice mountain ranges and stuff like that.

However, L3DT makes the features way too large. There's terrain raising in elevation for hundreds of miles, coming to a peak and then slowly falling off again. It doesn't really look like mountain ranges, rather like one big humongous mountain.

I played around with the options quite a lot, but here's what it generally looks like:

Horizontal scale: 8045 m (5 miles)

sea/land 50%
altitude range: flat (0%)
scale of features: tiny (0%)
Noise strength: full (100%)
Noise shape: fractal (100%)
Cliffs: none (0%)
erosion: strong (about 70%)
lakes: some (about 25%)

Firt of all, there's the problem I described above, with terrain being way too regular for my purposes. Second, the terrain is generally too high. Most of the land gets covered in snow, despite temperate climate. Things get a bit better when I make a more detailed design map, but then the landmass in itself looks more like a group of islands created by a lunatic than like a continent.

This program was probably not designed to meet my needs, so never mind if it just can't do what I'd like, but I thought I'd ask before giving up on it. Maybe in that case someone could point me to a programm better suited for the task.

[DSXC]

I think you'll find your horizontal scale isn't right.

The horizontal scale is the size of each pixel in meters. Since your map is 5 miles represent in a 2048x2048 matrix, you would need to divide your 5 miles by 2048 to set your horizontal scale (which is approximately 4m).

Try your settings again with a horizontal scale of 3.93m (or 4m which would be about 158 yards over 5 miles).

[Aaron]

Hi UncleBob,

Sorry, L3DT isn't designed to generate terrain at such a coarse resolution. The program was designed more-or-less to generate terrain for use in 3D games, and thee are very few 3D games that I'm aware of that would use a terrain resolution as large as 8km per pixel, as the visual results would be pretty poor. Indeed, as an example I present a ~560x560 kilometre region of central Italy down-sampled to 8045m per pixel:

Italy8000m.jpg (17.31 KiB) Viewed 316 times

[note the Mediterranean sea floor is not included in the SRTM dataset, so it appears flat]

We cannot resolve any interesting features of the terrain, so I would consider this data to be too coarse for use in 3D games. By contrast, the original data set was captured at 93m per pixel, which looks rather more detailed, and could be readily used for gaming purposes:

Italy90m.jpg (27.43 KiB) Viewed 316 times

This is the sort of range where L3DT was designed to operate (0.5m - 100m horizontal scale), and its behaviour outside this range has not been much of a design consideration.

If you were to do that in L3DT, you could generate the terrain at much finer resolution and then down-sample the output to get the coarser steps. I wouldn't generally recommend using a horizontal scale larger than about 100m per pixel, but in this case that would require you to generate an enormous map (160k x 160k pixels @100m/pxl) to cover the same area, which would be impractical.

Another approach may be to manually edit the design map to better control the heights and sizes of features, and be sure to use a very low heightfield to design map (HF/DM) ratio in the design map size wizard (i.e. 16x), so that the minimum amount of inflation is applied to the features of the map when generating the heightfield. This approach may work, but it would probably be a lot of manual work with the design map brush tool.

Best regards,
Aaron.

[UncleBob]

Thanks a lot for the reply, Aaron. I thought that the program just might not be designed for the scale, as it is indeed pretty useless in a 3d aplication. Generating at a finer resolution and the toning it down of course occured to me, but then I'd have to buy the program to achieve the size I need. While I'm sure that the program is totally worth it if one uses it a lot, I can't justify the expense for that one task. I might try your other tips though, let's see if it comes up with something usable.

I think you'll find your horizontal scale isn't right.

The horizontal scale is the size of each pixel in meters. Since your map is 5 miles represent in a 2048x2048 matrix, you would need to divide your 5 miles by 2048 to set your horizontal scale (which is approximately 4m).

No, little misunderstanding there. The aim is indeed every pixel representing an area of 5x5 miles (one map tile), resulting in a total area of 1.049e8 miles ^2, a large continent (Asia has about 1.723e7, but I'll have lots of water around it, so the actual landmass would probably be a bit larger than europe).