The first step is getting worldwide data. For a project of this scale, we don't need terribly accurate data but if you were curious what the data would look like, I've got you covered. I'd personally recommend two sources for worldwide topography and bathymetry together.

1. https://www.ngdc.noaa.gov/mgg/global/global.html
   • This site has the pros of being a simple and providing a single file format for the entire world to include both topography and bathymetry. I also like that it has the option to download an already georeferenced (.tif) file which I find to be a fairly universal file type for data of this caliber. Georeferenced (.tif) files can be loaded easily in almost any mapping program without needing to do any extra work.
   • The con is that it has 1 arc-minute resolution. This is likely fine for a small-to-medium sized piece on a worldwide extent. However, it may be a bit lackluster if you were to focus on more specific extents.
2. https://topex.ucsd.edu/WWW_html/srtm30_plus.html
   • This site has an improved resolution of 30 arc-seconds. Which will have a bit more detail than the above source. Although this will cause the data to be a bit bulkier to handle due to this increased size limit, if you needed better accuracy due to a more focused extent, this could be a requirement.
   • The con is that the downloads are not setup as conveniently as they are broken down into multiple tiles and may require a bit of conversion depending on the file type you would prefer to work with. You'll have to check and make sure your processing the tiles or converting appropriately.

From here we can simply set up the data into a format that allows us to apply some edits and calculations to fix potential issues that could stem from the way this data would need to be altered to make sure the wooden outcome isn't too difficult to work with.

Initially, the scale of the whole world fitting onto a 2' x 4' slab will result in a fairly underwhelming 3D representation. Relatively speaking, the earth is quite flat. In order to make the piece stand out, we would need to exaggerate the elevation values to an amount where they would be identifiable so that the mountains and topography can be more easily noticed and felt. This part is obviously removing any vertical accuracy of the piece but does provide a far more aesthetically pleasing look and feel.

Another major consideration is the fact that shorelines are often not perfect walls and are rather a gentle slope into the ocean. Although not true everywhere, it would be almost impossible to identify the coastlines due to how flat things are at this worldwide scale. Areas that had terrain near sea level would be a nightmare to fill with epoxy resin since its viscosity would not allow it to remain perfectly level especially over such large expanses. The inability to have a hard wall separating the shorelines from land would likely make it impossible to fill along an accurate shoreline on a practical level. As such to remove as much room for error as possible we can take shoreline areas and define them simply subtracting an appropriate amount of all the outlying raster cells. This will "drop" the ocean floors by a considerable amount creating clean walls for the continents, islands, and/or landmasses to sit upon. This will make it far easier to determine where pours should stop to maintain accurate coastlines while still retaining the bathymetry beneath. This process may also be repeated for landlocked lake/sea/water bodies.

You can check out and explore a 3D model below. It should allow you to compare in a few different ways the accurate elevations from the vastly altered one that would make a piece like this possible. In order to keep the file a manageable size, the resolution is a bit lower than the data mentioned above. Even at the full resolution, the accurate dataset appears completely flat! The "landmass shelves" are little less noticeable here, but its a pretty clear night and day between the two datasets.
For this example, I chose to add 1,000 meter "shelves" for the landmass shorelines and exaggerate the elevation and bathymetry by about 25 times the actual heights. This looks to be close to how the actual piece turned out. It was still an insane amount of accurate work required to get shorelines, lakes, and islands to work out well.

These alterations may not be necessary for smaller pieces at other scales, but a worldwide extent has these few unique challenges. There are, of course, a large number of other considerations that Curae was more aware of such as wood warping, meshing pieces, and proper sanding/pouring techniques that I don't have the expertise to talk about. However, I'm sure this was some of the data massaging they have gone through for such pieces. The results, of course, speak for themselves I believe as they are quite stunning. Hopefully, you've enjoyed the art in this fun little side project!