Version 2 of Terraform
The games countries only build on plains, grassland or river squares. They do this by checking a value “City build value”. I have not come up with an exact matching value for every square, but something close. So as to not upset the configuration of a game that may be saved with only minor changes. TerraForm marks the squares that a user has changed and at the SAVE function it re-evaluates the value only for the squares that change. (also for the 20 squares that are effected if this falls in the range of a city).
All Cities are checked for there proximity to seas so that the "by the sea bit" will be set. This can change cities that were built by the game that were later captured by the human player.
(See This)
The “allow hydro plants” bit is set for city adjacent to mountain or river square.
There is also a check for Illegal landforms. There are two that I know about.
1) Rivers that are only one square that do not connect to the sea. The game seems to be ok with this, but does not display a river square with a stream, only a bare river square. Look at the center square in the 3x3 island. It is a river.
2) The three 2X2 land squares connected by land bridges have strange attributes. Boats can pass through the land bridge connecting the 2x2 squares. Also land units can cross the bridges connecting the 2x2 squares. This never appears in worlds created by the game. It is flagged by Terraform, the user can save it or not.
There is also a bug that occurs quite often. The units that occupy the same square are linked by a linked list. This becomes corrupted sometimes. Mostly it is not noticed, but sometimes units disappear or seem to be in other locations. In drastic cases the game freezes or terminates.
This game
(SEE THIS) can be fixed by re-linking the units’ list. The new version of TerraForm checks when you open a file and offers to fix the SVE file if the user desires.
Version 2 of Terraform see first entry in this thread