Quick and dirty world building...

Is the blob landmass or ocean? We need a reasonable target hydrographic ratio and the land ratio, to use in finding a random world map filling procedure.

One way is to choose a target number, the lesser of two d% rolls. If less than, it's landmass, if greeter, ocean. Landmass is less likely and trends smaller, but we could still see vast continents or tiny oceans 

50 and 41, so a 41% chance of landmass. 36, a 36 m. km^2 continent half again the size of North America.

52 and 39, so 39% chance of land; 46, 46 m  km^2 of ocean adjacent to the continent.

46/82 ocean, HR roughly 56% so far. More than four hundred short of the half billion. On average it takes ten iterations to get to 500 m. km^2.

I have consistently made world mapping too hard. Quick and dirty world build my land and sea with d% rolls. Each number is the area of each bit of landmass or ocean. It's ocean if the # is greater than 29% or whatever your target land ratio is. Blob zero is at tht north pole, blob one is adjacent. This is quick and dirty, remember? 8-P

43, polar ocean 

65, adjacent ocean, may merge, 108 m. km^2 total, 0% land...

41, more ocean, 149 total

28, landmass!!! 28/177 is 15.82% land

Continue until we have an earth sized world, setting a default of ~500 m. km^2 surface area.

So far we have roughly the northern third of the world, the three ocean blobs would be a little more than down to ~30 degrees north latitude.

How about a situation? 

40, 25, a 25 year old woman rescues... 56, 24, a 24 year old woman. From drowning? 40 under 56%, yes, a flash flood, younger woman drove into deeper water than they expected and the car went floating.

Romantic? 50 over 44%, no, just a little hero worship. 25 gets 24 out of her car and onto dry ground like a wet rat...

Kitty, for Catherine, and Fanny, real name Sarah. Kitty is a paramedic and firefighter. Fanny is a dental hygienist.

Mass of aliens: 2 d% rolls, 46 and 55, normal range of 46 to 55 kg, or take the higher # and use +/-46%? That's a range of 30 to 80 kg, 66 to 176 #s, average of 121 #s.

Bilateral or radial symmetry? 60% chance bilateral, 44 is a yes. Bilateral evolved from 'fish'. That last is just a judgement call, crawled up into the mud with more that two pairs of legs? 36 under... 36%? Interesting. Yes. More than three pairs? 51 over 44%, so no, three pairs, a centauroid?

What chance of a survival game, pandemic or mega volcano? 46%, rolled a 35, so MV and pandemic at the same time...

43 and 48, a 43 year old man

39 and 49, another man, 39 are they related?

51% chance, 37, yes cousins, Mom's are or were sisters...

Yet another Oracle ..

D% roll- 43% chance of aliens; 76, which is a fairly strong no, a 76% chance that this isn't my usual starfish aliens, tramp merchant strange old worlds for fun and profit setting.

Strongly opposite that is medieval fantasy, which I am not interested in doing, either...

draw a line

Pick points to make a triangle.

stuff!

Oops!