This is a short guide I've made because of a comment I left in this guide: https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2956355437 ...explaining how to get the Perfect Location Achievement in Terra Nil: Vita Nova. A user there, helzilla, requested that I make a short guide to better explain what I meant. So here we are.

Start a new run of the first level, River Valley. You want to find a section of the map which is around 25 by 50 tiles with a single-tile-wide river running through the middle. The example image is 24 x 52 tiles. If there isn't a suitable location just retry until the map generates one. It is okay if the river bends or turns a bit just keep in mind you need usable tiles on both sides.

Now play the map as usual but do not touch this area. You want to progress all the way to the third stage, reclamation, before working on this area so you have all of the tools available to you. While doing this make sure to set the surrounding area up so you can burn your target section from two opposite corners. DO NOT UNLOCK THE RAINS. You can still do this with the rains going but it takes much more work.

First priority is power for the area. If there aren't enough rocks in good positions you can use the Calcifier but make sure any rocks you form are far away from the center of your work area. You need enough coverage to be able to cleanse the Wasteland with Toxin Scrubbers but don't place them just yet.

You need to widen the river. Birds and Beavers need a good number of water tiles. You can widen the river using Excavators (make sure you build the Research Centre so it becomes the one-tile laser version). You can do this from the middle or from outside but be sure to leave the center a single tile wide so you can use the Animal Bridge to connect the two sides.
Use a Water Pump to fill in the excavated areas if you need to. After that place your Toxin Scrubbers to remove the Wasteland and then use the Loading Dock to remove all the buildings while leaving the Wind Turbines if possible.

Think of the work area as being divided into quarters. You need two opposite quarters to be Forests, one of the remaining quarters to be Wetland and the one opposite to that to be Fynbos. The Wetland and Fynbos must both reach the center tile where the Animal Bridge will be. Choose your two Forest areas first based on which quarters you will be able to light fires near to but don't do anything yet.

First do the Wetland. Place the Animal Bridge on the center tile, if you haven't already, because you can't place it if one side of the River is a Wetland. By carefully placing Irrigators you can grow grass selectively to ensure an area you're converting to a biome won't go further than you want. This is part of why the rains make this whole thing more difficult as they convert Wasteland into Soil and then into Grass automatically. Place your first Irrigator so it includes the tiles in-line with the center of the area:
Place another Irrigator if one doesn't cover the whole Wetland quarter then place Hydroponiums on each to create the Wetland. The Frogs might move in but they will be very unhappy due to lacking Fynbos nearby. Don't worry if they move out as they'll come back eventually.

Our goal is to turn the work area into this:
Use Irrigators to add grass up to the Wetland on its side and just short of the middle on the other. Remember: the Fynbos quarter needs to reach the center tile so don't prepare the land in line with the Animal Bridge just yet. The single tile of Grass next to, and caused by, the River shouldn't be a problem even if it converts to a tile of Forest. Don't reclaim the Irrigators! Light both of those quarters using whatever you set up to do so. Once burned convert the destroyed buildings into Arboretums to spread the Forest over those two quarters. You may want to irrigate, burn and then place Arboretums in the quarter next to the Wetland first to try and get Deer to move in there rather than the other side.

Now use Irrigators to spread Grass over the Fynbos area. Place Beehives in a couple of trees right next to the Grass to convert it into Fynbos. Place a couple more Beehives in that Forest as food for Bears but don't place any in the other Forest quarter. Bears and Wolves can share some Forest but best to encourage Bears to be in one quarter and Wolves to join Deer in the other.

With everything set up you should have all six animal types for the map crossing over at the center tile:

1. Birds just need River, including the center tile, and should have been the first to move in.
   
2. Beavers need River and Forest so they should be happy and cross the center tile as well.
   
3. Frogs need Wetland and Fynbos but won't go far to find it. They will cross a single tile which is why we needed the two biomes so close together.
   
4. Deer are fine with Grass or Forest and should be crossing the Animal Bridge freely.
   
5. Bears only need Forest with Beehives so they are set, though they should roam across the Bridge as well.
   
6. Wolves need Forest to live in and Deer to hunt so wherever the Deer go they go, too.

So once all of the animals are completely happy, which should only take a minute, you get the achievement!

If some of the animals aren't crossing the Animal Bridge you can use the Sonic Beacon to nudge them towards it or the Animal Observatory to drop them literally right next to it so their living space will definitely include it. Then you simply wait for them to be completely happy. You can also use the Observatory if the map was already full of animals and so more can't spawn in the area. If the Animal Observatory is removed (again) you have to ruin their existing habitats elsewhere in the map so they leave there and respawn in the prepared area.

Here's how mine ended up:

I didn't do it quite right. I didn't manage things very well so I cut more rivers to separate the quarters so I could burn each safely. The Wetland didn't reach the Animal Bridge and the Frogs wouldn't move through the Forest and River to reach the Fynbos. Luckily I had left some Grass in the Forest next to the Wetland so I converted it (you can see it in the top-middle of the screenshot) and that encouraged the Frogs to cross the River to reach the Fynbos. Hopefully, with my near-failure, I've helped you do a better job.