How do i create a port city in Spore space mode?

I tried placing a city almost directly on the water but it just levels out the land separating itself from the water.How do i create a port city in Spore space mode?
You cannot create port cities anymore in the Space stage anymore unfortunately. This feature is only available in colonization and as such only makes a difference in that stage. Boats are not necessary. This goes along with the "Three colony rule" for planets, in which the only planets that have more than three cities are home planets.How do i create a port city in Spore space mode?
I'm not sure, but I think port cities only appear randomly on plants that you did not colonize.



After all the terraforming and visiting around I have done, I have noticed that the only plants with port cities, are ones that I did not make.



I could be wrong, but I think that's how it is.