I just started a new game on a new map with lots of water. Walking around, I noticed a huge oilfield. However, among the normal crude oil patches, there is also offshore oil -- on land, mind you! As I just researched automation, I cannot tell yet whether I could also place a deep sea oil rig there, but it just feels wrong to have offshore oil on shore. :-)

BTW: After I generated the map, I updated your mod to the latest version. Could that have caused wrong placement of the oil patches?

Hm, i will look into it. Do you use any other mods that might change the collison layers of ground tiles?

I was able to reproduce this. basically its just normal oil with another name, you wont be able to build oil rigs ontop, nor does it have the characteristics of the deep water oil introduced by this mod (single, isolated very high yield fields). but i will try to fix this for future releases

So I could use normal pump jacks to get at the wrongly placed offshore oil? BTW: I started a new game again and started exploring the area (nothing built yet). This time, I found a spot of crude oil (just one single puddle with a yield of 582 %) located on water. Here's a list of the other mods I've loaded besides Cargo Ships:
- Aquarium
- Asphalt Roads
- Bio Industries
- Canal Builder
- Dirt Path Redux
- Fish Slurry
- Nice Fill
- Pavement Drive Assist
- Realistic Ores
- Small Robots
- Text Plates
- Wood Gasification
Hope that helps -- and thanks a lot for looking into the issue!

Actually, I'm a bit pressed for time these days, so I probably won't have much time for playing until the holidays -- if I'm strong enough to resist the temptation, that is. :-D

the issue with deep sea oil spawning on land should be fixed with the newest update, i figured out whats causing it and it did not have anything todo with other mods.
the spot in water, when moving there (not on map view) did it say deep sea oil or crude oil? on map view it always says crude oil. good luck with your abstinence ;)

Thanks a lot for fixing it! And you were right, it's only "crude oil" in map view. When I moved there, the description is "Offshore oil", so it's only a wrong label, not a misplaced resource. It's not perfect, but as long as I can get at the oil I'm perfectly OK with it. :-)

Not related to this: You said on the info page that offshore oil not being shown in the map generator preview is a known limitation. Would it be impossible to show it in the preview, or is it something you just haven't considered important enough to implement yet? I understand that there may be more pressing things taking your time, Factorio/modding wise as well as in RL, but seeing offshore oil in the preview would make it so much easier to choose a map …

In the game, I'm fascinated by trains, so I want to have lots of connected land to have a large rail network. But since I found your mod, I've got intrigued by the idea to combine different forms of transportation, having ships deliver cargo which is then picked up by trains until it's distributed by belts and bots. (Automated vehicles could come into play as well -- in some future game.) Islands rich in resources would be ideal -- but often the generator brings up maps with mostly empty islands, or even no islands at all. If there is water that I don't have to cross in order to get to resources (because it's only lakes that trains can go around), I don't have a plausible excuse for using ships. Knowing that there really are rich oil fields in some big "lake" would be an excuse, though. The hours wasted generating maps waiting for THE map would be hours gained for playing … :-D

about the preview thing: i think it wont be possible to change this, since the oil is not generated like other resources in a deterministic manner but only when during the actual game patches of water are discovered.

For island worlds: i ve had good experiences with low-frequency, huge size water settings. but there also are some island-mods (check this mods dependencies)

Preview: So it is impossible to implement. That's too bad, but it can't be helped then. May I suggest you change the text on the info page? "Known limitations: Deep sea oil does not show on the "generate preview" screen when starting a new game" does sound as if it was something that could be fixed and you might set to work on it some future time. Just tell people outright that this is a limitation imposed by game mechanics you can't do anything about and you won't have to cope with questions such as mine anymore. :-)

Island worlds: I've used low frequency/huge size water before. Default settings in "Rail world" is "Very low" frequency for iron/copper/stone/coal and "Low" frequency for uranium/crude oil, all with size "Big" and richness "Regular". With frequency changed to "Low" for iron/copper/stone/coal, chances are higher that a patch will be placed on an island. I also reduced frequency to "Very low" and size to "Medium" for crude oil as an incentive to get the offshore oil.

"Islands worlds", which your mod recommends, generates too many too small islands for my taste. "New islands" looks more promising, even though it still has an "optical" glitch: A lot of green water is inserted, and the transitions between blue and green water look really ugly. But with this mod and the settings mentioned above, I seem to get maps just right for what I plan to build.