WIP World of Calen Ndor

[Korba]

Things start to get a bit more interesting now (and colorful).

The next task is to add the effect of the major mountain chains on rainfall. As the wind blows and encounters a mountain range it rises cools and any moisture falls as rain. on the other side of the mountains a rain shadow forms because all of the moisture from the air has already fallen.

So using the prevailing wind directions shown previously the rainfall map can be modified to show areas that would be drier than expected and wetter than expected (the black lines represent the mountain chains):



Next stage is ocean currents. A bit of a dark art this one so I'm going to stick with the basic rules and fly by the seat of my pants. Been a while since i did any oceanography so if anyone in the know sees any glaring errors please let me know.

The first rule is warm water flows from the equator to the poles and vice versa. The ocean currents are affected by Coriolis Force and so bend to the right in the northern hemisphere and to the left in the south. Obviously the shape of the land will affect flow so using these basic rules my worlds ocean currents look as below:



Ocean currents are very important at distributing heat so i can modify the earlier heat map as the ocean currents shown above carry warm water to the poles and as cold water returns. This gives an ocean temperature map as below:



Although its unlikely a fantasy map will never show ocean temperature this is very important on later land types. For example the warm ocean current flowing past the northern island arc means they will be much warmer than the latitude itself would suggest. The ocean also acts as a thermal blanket keeping costal areas milder while inland regions cool much faster. So using this and the ocean temperatures i have spread the effects onto the land to give the land average land temperature map:



Just for the sakes of a pretty map i combined the two temperature maps:



So now we have all the essential data i need to do the map. The next stage is producing a climate map showing how the tundra, desert, rain forest etc will be positioned.

[Karro]

Bravo, bravo. I love the step-by-step logical world-building approach. I attempted to do this on my own map, but my own understanding of these facts was much to feeble to reach quite the level you are going to. In particular, I missed the consideration of how oceanic currents affect overall climate and temperature.

You're efforts are certainly commendable!

[Korba]

Thanks Karro

I need to define the landscape now based on temperature and rainfall. I'm going to use the Köppen climate classification. The five major climate classifications are:

A - Moist Tropical Climates are known for their high temperatures year round and for their large amount of year round rain.

B - Dry Climates are characterized by little rain and a huge daily temperature range.

C - In Humid Middle Latitude Climates land/water differences play a large part. These climates have warm,dry summers and cool, wet winters.

D - Continental Climates can be found in the interior regions of large land masses. Total precipitation is not very high and seasonal temperatures vary widely.

E - Cold Climates describe this climate type perfectly. These climates are part of areas where permanent ice and tundra are always present. Only about four months of the year have above freezing temperatures.

From - http://www.blueplanetbiomes.org/climate.htm

On my map this gives:



The Wikki entry has a full set of climate types. I will use the sub groups when i map in more detail but for the moment i will be working on the following general guidelines:

A - Tropical Rainforest
B - Desert
C - 1 - Mediterranean
2 - Temperate Forest
D - 1 - Grassland
2 - Boreal Forest
E - Polar Ice and tundra

type 1 climates are from 0 - 30 degrees and type 2 60 - 90 degrees.

Of course these are very basic but allow me to map the background terrain of any area and then add in local climate effects and human influence more realistically.

The next stage is to actually try and make some pretty maps, but I'm happy that unlike all the previous maps i have tried to make i won't have to spend hours worrying about what the air and ocean currents, latitude and prevailing wind are doing.

[Korba]

I have a had a little bit of time to start on one of the maps in more detail. I'm choosing the centre southern continent. It is about 550 miles East to West and 400 miles North to South making it similar in size to France.

As you can see from the previous map the northern area is desert similar to North Africa and then down to A Scandinavian climate in the South. The range of temperatures is large because my southern area doesn't have the Gulf Stream equivalent keeping it artificially warmer. So far i have only added the drainage pattern. I have put quite a bit of thought into this:



The higher the number of rivers is obviously related to the amount of rain in the area. The shape of the rivers is related the the hills and mountains in the area (which will be clearer when i add them!)

Next stage is to add the mountains but I'm still deciding on the style of map to try.

[Karro]

I have a had a little bit of time to start on one of the maps in more detail. I'm choosing the centre southern continent. It is about 550 miles East to West and 400 miles North to South making it similar in size to France.

So, based on this, does this mean your planet is considerably smaller than Earth?

I ask because, given the size of your continent (which appears to stretch from the 30th to 60th parallels), if this planet were the same size as Earth, then this continent would appear to be much larger than France (which is about 211 sq. miles vs. 220 sq. miles roughly for this continent by your figures).

By my admittedly rough calculation, if your continent is about 550 miles across, then the circumference of your planet at the 60th parallel is somewhere between 3,000 and 4,000 miles (based on my very rough finger-ruler measure of the number of times you can count the width of this continent across the 60th parallel). Mathematically, the circumference at the 60th parallel is 1/2 of the circumference of the planet at the equator, which gives you a planetary circumference of between 6,000 and 8,000 miles. The Earth, on the other hand, has a circumference of almost 25,000 miles.

[Korba]

Thanks Chuck.

Thanks for pointing the scale problem out Karro, i was out by a factor of 10 The continent should be 5300 miles east to west and 3500 north to south so its more like the size of the US and Canada (very roughly).

Its the first time i have worked at such a large scale so I'm going to have to do some rethinking because as much as i like my drainage pattern I'm currently working at 3.5 miles per pixel.

The sizes (in miles) each continent are below, the image is 2500 by 1250 pixels. The circumference of the earth is roughly 25'000 miles so hopefully my measurements are right this time.



Back to the drawing board

[Karro]

Thanks Chuck.

Thanks for pointing the scale problem out Karro, i was out by a factor of 10 The continent should be 5300 miles east to west and 3500 north to south so its more like the size of the US and Canada (very roughly).

Its the first time i have worked at such a large scale so I'm going to have to do some rethinking because as much as i like my drainage pattern I'm currently working at 3.5 miles per pixel.

The sizes (in miles) each continent are below, the image is 2500 by 1250 pixels. The circumference of the earth is roughly 25'000 miles so hopefully my measurements are right this time.

You're welcome. It just felt wrong, scale-wise, so I had to dig into the figures, out of sheer curiosity, and then felt compelled to share my discovery.

And I had the 25,000 mile figure sitting in front of me when I wrote my response, and yet still wrote 220,000 when citing the earth's circumference. Of course, that's what I meant (I had just looked it up, and found the figure 24,901.55 miles or 40,075.16 km for the circumference).