Frank Gregorio has asked me to collaborate on an educational project that shows the Yucatan asteroid impact 65 million years ago. The base of this will have to be to discover, and from that, create a texture map that shows the Earth as it looked like before
the impact. That is the task i am setting forward to do here.
Now, first of all, we will have to define what resolution to create the map in. Frank wants a very high resolution, but that is impractical if one is to show an animation, and there is no point in going very close to an Earth that we cannot know what looked like in detail
- anything closer than a general representation will necessarily be fiction, and so not usable in an educational setting anyway. However, to be really useful, the map should have print-quality resolution. So, a middle ground is called for:
A 4k map (4096x2048 pixels at 72 dpi) will give us a 300 dpi print quality at A4 (slightly higher and narrower than the american letter format). This is larger than the format of most books.
So, it makes sense to make it a 4k map. When this is to be used in an animated Celestia add-on, it will have to be at 1k or 2k anyway, to make for reasonable framerates.
However, it is entirely possible to build a Virtual Texture on top of the 4k map that shows greater detail for the impact area. By using the BMNG dataset, one can get at least up to 64k resolution of the Yukatan, if that is desirable, though i cannot imagine that high resolution to be necessary. More on that later.
For now, i will outline the project.
Before creating the map, we need to know as much as possible on what the Earth actually looked like 65 million years ago. Frank has sent me this map:
... We will need solid documentation on how this information was achieved. The reason i ask this, is because even though this view might work well for an animation of the impact, t is not good enough for a map that can be used for other purposes (say, in a textbook on the subject); for this, we need to verify how sound the data is, where it comes from, who made it, etc...
If this map is our state-of-the-art knowledge of the 65MY Earth, i will use it as a base for our 4k map.
2. Building the map
I will base our map on the BMNG dataset, since it is both publicly available and the best quality maps out there today. It is available for all months of the years, so we will probably create a hybrid of several months to get as close to the ice coverage of 65MY as possible, and then modify coastlines, vegetation colors, etc. to match what info we have. But there will only be modifications to a pixel if we know something about it!
Here is the BMNG Earth, of a nothern winter month:
As you can see, it is very different from the 65MY image above. However, it is our current reality (or last years, at least).
The first challenge, then, is to define *how* to change the BMNG map.
Frank, can we start with getting what info there is on the 65MY picture above?