How to allow certain buildings to be built on certain terrain tiles?

[hypsandar]

I decided to add a farming system to my map, its working fine. However, i don't want users to be able to plant on snow, ice and desert terrain tiles.

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A unit places a building, after a time has passed and building has completed it turns into a certain plant item that can be sold to the markets.

 

[Pyrogasm]

There's not going to be a way to modify it so the pathing map shows red squares over the ground in snow/desert. The best you can do is detect when a unit is issued the order to build a farm, check if it's in valid terrain (there's a 'terrain type at LOCATION' check), and if not order the unit to stop while displaying a custom error message with something like SimError.
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In the OE make the building a shop that sells 1 of the plant item with 0 initial in stock, 1 max stock, and the recharge time being how long you have to wait for it to mature. With a trigger catch when the building sells the plant item and remove the building from the game.

 

[IcemanBo]

I can't check it right now. but iirc UMSWE had some feature to modifiy pathability/buildability for certain terrain type.
It's worth to check it out, but Pyrogasm's solution also sounds like a solid way, and you have benefits with printing custom wrnings.