pak128.br-experimental: please make small rivers navigable

[neroden]

I've been experimenting with creating large maps with simutrans-experimental.  I've been trying to get rivers which are useful for trade early on.

The first noticable problem is that cities don't particularly cluster near rivers.  They should (historically, they really did).  This would require tweaking the city generator though.

The map generator doesn't create many rivers by default; not nearly enough for a satisfying large map.  However, you can turn the number up.  This also mitigates the problem with the city locations, as they're more likely to be near a river if there are more rivers.

The real problem, however, is that almost none of the initial rivers created are navigable -- on a large map.  I think the river types are chosen by starting with streams and enlarging when two rivers meet -- I'm just guessing here, but it matches the results I see.  The trouble is, on a large map, the rivers rarely meet.  If you turn the river count and length up high (I maxxed both out), they will meet often enough to make *small rivers* (rather than just streams), but you will still get very few wide rivers on the map.

Accordingly, in order to make rivers useful for trade on a large map, small rivers should be navigable.  (Thematically, they were navigable by smaller canal boats, though not by ones with large drafts -- weight limits should deal with this, with a smaller weight limit on small rivers than large rivers). I think this is an easy change which would make the early game a lot more fun.  Streams can remain as the "just an obstruction" type of river.

EDIT:
To be clear on the problem, this is related to the use of large maps, because rivers are one tile wide, not a width proportional to the number of tiles in the map.  With smaller (512x512) maps the rivers meet appropriately and create enough "Rivers" and "Wide Rivers" for trade.  But with large maps, such as are used with Experimental, there are very few "Rivers" and "Wide Rivers".  I think the simplest and best solution is simply to make "Small Rivers" navigable in the experimental version of pak128-britain (not in the standard version).

[jamespetts]

Neorden,

thank you very much for your feedback. I have moved this to the Pak128.Britain board, since the issues that you describe are not specific to Simutrans-Experimental (the issue is equal both for Experimental and Standard - even Standard distinguishes between navigable and non-navigable rivers), but relates more to Pak128.Britain.

I do agree that the default number of rivers should be increased - I shall change the simuconf.tab value for that on the next release. Another value that has a substantial impact on the number of larger rivers is the minimum river length. Reducing this from 32 to 8 (as will be in the next version of Pak128.Britain-Experimental) enables a larger number of rivers to be generated (when setting a higher number, most often, fewer rivers are generated), many of which are very short tributaries feeding into larger rivers. Setting the minimum length of rivers lower tends, therefore, to allow more larger rivers.

As to making cities tend to grow near rivers, this, I understand, has been suggested in the past for Simutrans-Standard. Whilst it would be a good feature, it would require a major rewrite, rather than just tweaking, and was considered impracticable.

[AP]

I agree with this topic wholeheartedly, I've been messing around with recent releases and one of the first things i end up doing is using the public player to "widen" all the river. My own thought had been that perhaps speed restrictions could apply to narrower rivers, rather than making them completely impassible?

Shame about the city generator thing, but understandable.

[The Hood]

I noticed that for some reason speed limits on ALL rivers in the latest version of pak128.Britain were 50km/h making them all navigable!  I have now sorted this out, and all but the stream are now navigable, but with different speed limits on each.  This will be in the next release of pak128.Britain standard, or you can get the sources from sourceforge and compile yourself.