Gigantica -- A Study in Maximum Habitable Planet Size

[Turambar]

Hi Turambar,

The algorithm was supposed to take everything into consideration, including the heightmap and the realistic placement of topography. I kept switching from Photoshop to Wilbur over a dozen times, making layer masks for each new layer and juxtaposing them together at the end. Sometimes I experimented with juxtaposing two identical images but enlarging one and setting the blending mode to screen, for the purpose of eliminating that "Wilburified" look and to create some natural lakes.

The Wilbur process relies on several applications of Erode (Precipitation) followed by incise flow; this pattern is repeated several times with various entries for the incise flow variables. In the end, I've run through the entire image to adjust coasts and contour lines.

Finally, I've overlain a bitmap of the Wilbur image and set the blending mode to vivid light.

Peter

Thanks Peter! I wish I had the skillset to build an algorithm like that. That said, you and others on here have been inspiring me to want to take on a "ground-up" redo of my tidally locked world from plate tectonics to climate. I'll just have to figure out how to use Linux and create a partition I guess.

Does this image look any better than the last? Am I getting close to realistic topo?

Peter

Yes, I think the new map definitely looks better, especially the mountains and coasts. I also like the addition of the lakes. Was the idea in removing many of the rivers that most wouldn't be visible at this scale? My only two things I would note is that I like the original rive color better (purely personal preference), and secondly, while the mountains look much better over all, the peaks look a bit blurred and might look better if they were slightly sharper or more defined.

[Naima]

Thanks Naima,

Yes, I'm personally never completely convinced about any complex calculation unless I can reproduce and cross check it with a separate algorithm. That's why I generally use both Clima-Sim and ExoPlaSim together (plus a couple spreadsheets), even though both have their limitations, most importantly a lack of ocean current modelling among others. Thus, to account for the influence of ocean currents, I'm intending to simulate the effect manually by painting a 10-15 C temperature change in the appropriate areas using worldbuildingpasta's blog as a guide. I figure that Azelor's tutorial is fantastic for Earthlike planets (as is Artifexian's), but as soon as the parameters stray far from Earthly standards, (such as the Polar cell disappearing with a 4-day rotation, for example), I find it difficult to trust my own calculations, or rather my ability to follow complex guidelines without error. Unlike a human brain, the GCM software always considers every programmed variable and follows every step in an algorithm, although sometimes the equations themselves are based on approximations and assumptions. Perhaps in 20 years, conworlding will be done completely by software, which will create every aspect of your world with scientific accuracy and high-precision resolution. I dread that day, for I believe such a feat will exise all the fun from conworlding!

Peter

Consider that those programs are also approximations and aren't really thrustable in my point of view, the best course would be if you want the perfect most plausible climatic reconstruction consider getting the help of professional climatologists, may be there are some forums on that topic, I don't know, but it depends on your time, willingness and needs I thing.

[Naima]

Update: I've tried to make the first continent even more realistic, using another experimental method (that I forget the exact algorithm for, unfortunately.) Here it is:

Attachment 133825

Is this any better?

This is much better, probably you used a more conservative approach to the mountains , the other ones were too eroded and resulted in getting more flat , I think this is good and realistic.

[MrBragg]

Consider that those programs are also approximations and aren't really thrustable in my point of view

That is, of course, true, though especially for the case here where the parameters deviate quite a lot from the N = 1 example we have in Earth, I think Peter's approach in using ExoPlaSim has a lot of value. Don't get me wrong, I really like the climate tutorial here, though I think that by knowing the blindspots and limitations of the programs and combining their outputs with intuition seems a good approach for capturing effects that might otherwise go unnoticed by simple eyeballing.

[worldbuilding pasta]

Climatologists generally make their judgements by running models, and ExoPlaSim is a model built by climatologists for the purpose of determining exoplanet climates. It's not the best of those models, but the better ones generally require supercomputers to run. You cannot trust it completely (though it's biggest issues are well known and can be accounted for to some extent), but there's not really anything else more trustworthy that's within our reach.

[Naima]

That is, of course, true, though especially for the case here where the parameters deviate quite a lot from the N = 1 example we have in Earth, I think Peter's approach in using ExoPlaSim has a lot of value. Don't get me wrong, I really like the climate tutorial here, though I think that by knowing the blindspots and limitations of the programs and combining their outputs with intuition seems a good approach for capturing effects that might otherwise go unnoticed by simple eyeballing.

The realistic climate portrait is so complex that even small factors can influence whole areas, like the change of 1 degree in temperature...
One example is the uneven basin and connection to water sources can alter also the Salinity level of portions of seas and this affect also the evaporation which in turn affects the local climate and so on ...



This is why I think that perhaps the algorithms can help a bit but in the end its basically pure guess work ... informed but still guess work.

[worldbuilding pasta]

Exoplasim doesn't even have detailed enough ocean dynamics for salinity to matter much; so far as the model is concerned, the oceans are all 50 meters deep. Incorporating a complete ocean model would add a lot more computational weight and probably require each model be run for about 10 times longer (after accounting for the extra computation), though the developer has expressed some interest in adding the option in the future. These sorts of fine ocean dynamics aren't quite as impactful as they're sometimes made out to be (particularly not at the coarse resolution of the model used here), but nevertheless there are indeed significant shortcomings to the model, and you should generally pay more attention to the overall "shape" of the global climate it predicts rather than the specific results at the level of individual grid cells.

But I still trust it a lot more than my own intuition. There simply isn't any good way to balance the myriad factors that play into global climate without sitting down to do some maths, and at the end of the day this model is basically just an automation of that process.

[Naima]

Exoplasim doesn't even have detailed enough ocean dynamics for salinity to matter much; so far as the model is concerned, the oceans are all 50 meters deep. Incorporating a complete ocean model would add a lot more computational weight and probably require each model be run for about 10 times longer (after accounting for the extra computation), though the developer has expressed some interest in adding the option in the future. These sorts of fine ocean dynamics aren't quite as impactful as they're sometimes made out to be (particularly not at the coarse resolution of the model used here), but nevertheless there are indeed significant shortcomings to the model, and you should generally pay more attention to the overall "shape" of the global climate it predicts rather than the specific results at the level of individual grid cells.

But I still trust it a lot more than my own intuition. There simply isn't any good way to balance the myriad factors that play into global climate without sitting down to do some maths, and at the end of the day this model is basically just an automation of that process.

Indeed but what I mean is that I do not put blindfaith in those tools, I use usually some when I have no clue on whats going on otherwise I use experience, but indeed for alien planets it can save many headaches , and on my to do list is make a program that can implement the basic stuff of climatology to automate the process but still had no time to start on it .

[Peter Toth]

Personally, even if I had a supercomputer outfitted with the most accurate climate modelling software available, I still wouldn't be completely satisfied because the tectonics--the foundation on which my conworld lies--is based on my very simplistic understanding of the subject. I'm sure this is Charerg's specialty, but in my case I have to confess my ignorance about whether the tectonic history I've depicted for Gigantica is plausible. I have over a dozen plates moving in various directions, but would those motions actually occur in real life on a planet so different from the Earth? Because I can't be certain, I'm not inclined to max out on the climatological accuracy, although perhaps in the future, when I've learned more of the science, this will change. Personally, I would appreciate a program that could simulate plate tectonics like Tectonics.js, but with much better resolution and accuracy. However, that kind of ruins the fun of worldsmithing.

Here's another rendering of my first continent, which I'm continuing to develop due to a little bout of perfectionism. Thank you Turambar and Naima for the feedback regarding the "erodedness" of my mountains. I've taken that into consideration and significantly reduced my iterations of precipitation erosion. I'm wondering if this is perhaps an improvement over the last, although I'm still in doubt over the continental shelves and bathymetry.



Let me know.

Peter

[Turambar]

Personally, even if I had a supercomputer outfitted with the most accurate climate modelling software available, I still wouldn't be completely satisfied because the tectonics--the foundation on which my conworld lies--is based on my very simplistic understanding of the subject. I'm sure this is Charerg's specialty, but in my case I have to confess my ignorance about whether the tectonic history I've depicted for Gigantica is plausible. I have over a dozen plates moving in various directions, but would those motions actually occur in real life on a planet so different from the Earth? Because I can't be certain, I'm not inclined to max out on the climatological accuracy, although perhaps in the future, when I've learned more of the science, this will change. Personally, I would appreciate a program that could simulate plate tectonics like Tectonics.js, but with much better resolution and accuracy. However, that kind of ruins the fun of worldsmithing.

Here's another rendering of my first continent, which I'm continuing to develop due to a little bout of perfectionism. Thank you Turambar and Naima for the feedback regarding the "erodedness" of my mountains. I've taken that into consideration and significantly reduced my iterations of precipitation erosion. I'm wondering if this is perhaps an improvement over the last, although I'm still in doubt over the continental shelves and bathymetry.



Let me know.

Peter

I think the mountains look fantastic. I appreciate your commitment realism even though there will of course always be gap between world creation and scientific perfection. You're certainly getting closer to realism than most.