somebody put a muzzle on this twink

Initial Observations

My first impressions of the space were based loosely on the way the epilogue is shot. I assumed the space looked something like this:

Grace and Rocky walk down from the house to the beach, and then up the beach away from the arch formation. This scene geography is maintained until we cut to Grace standing on the beach in front of his classroom. I had assumed these shots were continuous, and Grace had walked up the beach from his house directly to the classroom.

However, upon closer analysis, this actually appears to be a discontinuous cut. Rocky is no longer present (or at least not shown) during this final scene with Grace and his Eridian students, and if we take a closer look at the backgrounds of each shot, it becomes apparent that these shots don't share geography at all. What to do?

Breaking Down the Shots

I started by making a storyboard of the epilogue to break everything down (big kudos to @aroace-ryland-grace's Project Hail Mary library! It was super helpful!).

There's four main shots that provide a lot of information about the biodome's layout.

Shot 9: Pan of Rocky and Grace walking on beach

Shot 9 shows where Grace's house is in reference to the arch formation.

Shot 8: Descending through biodome ceiling

In Shot 8, the camera descends through the ceiling of the biodome, giving us a wide shot down the length of the beach. In the distance, we can see some faint blocky outlines indicating xenonite barriers. Helpfully, we can also see a very tiny Grace and Rocky walking, which, when combined with Shot 9, means that this is showing a view down the beach away from Grace's house and the arch formation.

Shot 24: Wideshot of classroom and surrounding beach

The widest view we get of the classroom is in Shot 24. There's still no visual connection to any of the shots we've seen featuring the arch or the house, but behind the classroom is a very distinctive rock formation that may come in handy later.

Shot 21: Rotation from Grace's feet; Grace picks up sand, walks away from water

Shot 21 faces away from Grace's classroom, giving us another view of the landscape. This isn't the same view we got in Shot 8, nor is it facing back towards the arch formation like I had initially assumed it must. The classroom has to be in another area, but there isn't enough information from the shots alone to fully reconstruct the space.

Now we have to turn from what's explicitly shown to what the real Earth location used for shooting looks like if we want to keep going.

Returning to Earth

The scenes on Erid were shot at the on-Earth location of Durdle Door, which is the arch formation we can see throughout the epilogue. I recreated ten shots in a Google Earth project file to try and piece together what we know so far.

Grace's house is very obviously located next to Durdle Door, which made it relatively easy to place.

Durdle Door is part of a larger promontory at the end of an isthmus. A wider angle facing the coast shows the full formation.

But wait! What's on the other side of that isthmus?

It's Shot 24!

Now we know where Grace's house and classroom are in reference to each other. This gives us the necessary geography to stich together what we know based on Shots 8 and 21.

Shot 8 gives us a view to the west of Durdle Door, all the way down to a set of rock formations called Butter Rock and Bat's Head.

Shot 21 gives us a view east towards another promontory called Dungy Head.

Bat's Head and Dungy Head provide the outer bounds for the length of Grace's enclosure on either side of Durdle Door. We also get some sense of how far out in the water the barriers are from Shots 19 and 24.

Shot 19: Rocky sits next to Grace

Speculation Time!

Based on this information, we can approximate some outer bounds for Grace's biodome:

Dimensions:

Total Area (enclosed by yellow perimeter): 1.96 km2

Land Area (highlighted in green): 0.91 km2

Biodome Length (purple): 2.5 km

Biodome Width (blue): 0.91 km

Grace's dome is pretty big! The width here might be a little generous, but based on what we can see, Grace has a couple kilometers of the Dorset National Landscape recreated for him to live in. That's a pretty sweet deal, honestly. Much better than his living situation in the book.

The setup of his house and classroom on the isthmus is also pretty logical. Their proximity is much closer than I had assumed. There's likely a tunnel within the isthmus that leads to the classroom, and possibly some other areas Grace and the Eridians can access for face-to-carapace interaction. As Grace gets older, there's even the potential for constructing an elevator straight down from his house to the classroom level instead of making him climb all those stairs. Very accessible!

I'm very pleased that not only is everything in those shots part of the real landscape (though they've obviously added VFX to get rid of the grass), but that the arrangement of Grace's home seems to be well-thought out. It would've been very easy to CGI the whole landscape. But it's not! It's Earth! Grace gets to have his very own little slice of home, with some Eridian touches.

I can't help but think that he and Rocky must have gone through so many landscapes in the Don't Go Crazy Room on the roadtrip to Erid until they found one Grace really, really loved.