terrainr advertises itself as a package for landscape visualization in R and Unity. This vignette focuses on the Unity half of the equation – specifically, on how to mostly-automatically import tiles into Unity. If you’re interested in the R half of the package, refer to (the overview vignette)[overview.html]. Note that this vignette will assume you already have Unity installed on your computer.

In order to import terrain tiles into Unity, we will first need to have some data worth importing! For the purposes of this vignette, we’ll be using data from the USGS National Map downloaded using get_tiles, but note that you can use any raster data for this process.

First things first, I’m going to use the geocode_OSM function from tmaptools to get the latitude and longitude of Zion National Park, out in Utah. We’ll use this area for our visualization today:

zion <- tmaptools::geocode_OSM("Zion National Park")$coords

Our zion object now contains the x and y coordinates for a spot near the middle of Zion National Park. Let’s go ahead and turn that into an sf object, then use set_bbox_side_length to add a buffer around the point coordinates – we’ll download data for the entire 8 kilometer square around the central point:

library(terrainr)
library(sf)
library(magrittr)

zion <- data.frame(x = zion[["x"]], y = zion[["y"]]) %>% 
  st_as_sf(coords = c("x", "y"), crs = 4326) %>% 
  set_bbox_side_length(8000)

And now we can go ahead and download data for our area of interest, then merge the downloaded tiles into individual rasters. For more on this process or what these functions do, check out (the overview vignette)[overview.html].

Fair warning – downloading this amount of data can take a bit of time! You can optionally add a progress bar to the get_tiles download by calling library(progressr) and then handlers(global = TRUE) before running this code.

merged_tiles <- zion %>%
  get_tiles(services = c("elevation", "ortho")) %>% 
  lapply(merge_rasters)

We’ve now got our data downloaded! Our next step is to turn it into a data format we can import into Unity.

As of terrainr 0.5.0, the way to do this is via the function make_manifest. The first argument to this function is the elevation raster you want to use as a heightmap – in our case, merged_tiles$elevation. The second argument optionally takes the image overlay you want to put on top of that heightmap. In our case, that means everything we need to provide is in the merged_tiles list:

make_manifest(merged_tiles$elevation, 
              merged_tiles$ortho)

After a moment, this function will spit out a number of files: our heightmap and overlay tiles, all prefixed with import_, a C# file named import_terrain.cs, and a final file named terrainr.manifest (note that all of these names can be changed via arguments to make_manifest, but for simplicity’s sake I’m using the default names now).

Now go ahead and open Unity. From the main “Hub” menu, click “New” to create a new project. Set the project name to whatever you want, then click “Create”.

Go ahead and move all the files from make_manifest into the root directory of your new Unity project. Then move the import_terrain.cs file into the Assets directory inside that folder (but leave everything else in the root directory!).

Go back to Unity now. A second after you click into the window, you should notice a “terrainr” menu appear in the top bar. Click that menu, then the only option in the drop-down. A menu should appear; click “Import” to import your tiles into Unity.

The importer menu will disappear, then Unity will take a minute or two to import all your tiles. Depending on your data, you may see something that looks like this:

That’s perfectly fine! Right click on the “Scene” window in the middle, and then press and hold “S” on your keyboard to move the camera back. After a second, you should see your terrain surface!

You can now move around your surface by right clicking on the image and moving around with the W-A-S-D keys on your keyboard. Note that your movement speed starts off very slow, and then accelerates over time.

And ta-da, you have a surface in Unity! You can go ahead and customize the scene further (I’ll usually then click on “Directional Light” and change “Render Mode” to “Not Important” and “Shadow Type” to “No Shadows”), fly around and across the scene, or do whatever else you want!