[Freeciv-Dev] Re: Land Reclamation (was: Chunnel)

[Jeff Mallatt <jjm@xxxxxxxxxxxx>]

At 2000/03/25 13:37 , Cameron Morland wrote:
>I've formed a bit more specific plan. (The initial patch simply fixes the 
>code so that the ruleset can modify something it appears to be able to.)
>
> * transformation of water to swamp
>
>"Reclamation of inundated lands has been carried out with particular
>success in the Netherlands since the 13th cent. Shallow sea areas are
>enclosed by dykes, and then the water is pumped out, section by section. A
>large inlet of the N. Sea, called Zuider Zee (Ijsselmeer), has been almost
>completely reclaimed during the 20th cent." (Cadillac Modern
>Encyclopedia: Land Reclamation)
>
>So this is a reasonable thing to do. I'd say that the 13th century
>precedes "Explosives" --- gunpowder barely existed in 13th century Europe.
>So Engineers are not required; settlers should be able to reclaim ocean
>once they have some technology (bridge building for now, better
>suggestions?). This is accomplished by making irrigated ocean turn to
>swamp. It's only possible for ocean tiles with water on three sides, and
>takes a very long time. Note that for doing this, the ship must stay on
>the tile, and no other ship may pass through. If they do, the settler
>stops irrigating.

However, from:

"By about AD 1000, however, the terpen area had been completely enclosed by
dikes. The controlling of water levels within the dikes developed into the
practice of reclaiming tracts of lowland from a body of water (see polder).
By 1667 the making of polders had developed to the point that the damming
of the Zuiderzee was proposed. A feasible method, however, was not
forthcoming until the flood of 1916 hastened the adoption of a plan
developed by Cornelis Lely. In 1927-32 a dam 19 miles (30 km) long, known
as the Afsluitdijk ("Enclosing Dam"), was built across the Zuiderzee,
separating it into the outer Waddenzee (open to the North Sea) and the
inner IJsselmeer (Lake IJssel). By the early 1980s four polders, largely
agricultural land, had been created through an elaborately constructed
system of pumping stations, dikes, sluices, and locks.          Nearly half
the IJsselmeer of the 1920s (626 square miles [1,620 square km] of a total
1,328 square miles [3,440 square km]) has been reclaimed and the
much-reduced IJsselmeer has gradually become fresh water. The completion of
a proposed fifth polder, Markerwaard, was the subject of debate in the late
20th century." (Encyclopaedia Britannica: Zuiderzee)

we can see that large-scale reclamation was not "feasible" until the 20th
century.  I think that sea reclamation should be a Terrain Transformation,
not an Irrigation.  This, of course, should only affect the terrain ruleset
-- any of irrigation/mining/transform should be allowed on ocean tiles by
the code.

>zuider.diff sets it up so if the terrain.ruleset allows irrigation of
>ocean, if three adjacent squares are not ocean and the player has bridge
>building. TODO: make it work with the goto command, figure out what to do
>about harbours/platforms and trapped ships.

goto command:  What's the problem?  Do you mean "connect command"?  If so,
I'd say to not implement it for now (which, I think, requires some new,
special code to keep the connect command from being available when on ocean
tiles).

harbours/platforms:  When ocean turns into land, check for cities within a
city radius of the new land square, and for any harbours/platforms in
cities that are now land-locked, destroy them with a message to the player
(perhaps they could be "sold", rather than just destroyed).

trapped ships:  The player should have to do some things for himself.  If
he traps a ship, tough.

Also, could you send your patch as a unified diff ("diff -u" or "diff
-ru").  I can't even tell what file to apply zeider.diff to.

jjm