Friday 11 August 2017

US 2017 Total Solar Eclipse Animation

I've only just started paying attention to the fact that there's a total solar eclipse in the United States on 21 August this year. What made me really take notice were the imaginative, amusing and bizarre maps people have been posting online - all good fun and often pretty interesting too. What seems to me to be missing - and absolutely essential, of course - is an animated eclipse gif showing the path of totality, towns and cities, a bit of terrain and some roads. So, I grabbed the geodata from NASA and spent a couple of hours playing around with it to make this thing you see below. This is an extract of the full file, in gif format. The full gif is over 100MB, so I've created a video file instead for the final file at the end of this post, below - and also posted on twitter. Click an image to see it in full size.

Note the small part of the path of totality in Montana

Nashville looks like the place to be

I also extracted a series of animations covering the whole US, in separate parts, so that the whole of the path of totality has been giffed, as it were. These are pretty big files and if I add them all here not only will it may crash your browser but it will also probably be a bit too bamboozling with all the animations going on at one time. Here's part 1 and part 2 below. The rest I'll keep to myself for now.

Part 1 - at 50 frames per second
Part 2 - also at 50fps

I just did this out of curiosity and to learn a bit more about the event. I thought it would be interesting to see for myself where the eclipse will go. I remember here in the UK back in 1999 when we had a total eclipse, but I didn't manage to get down to Cornwall to see it properly. Just take a look at this video to see how long ago this now seems. I was in Glasgow at the time and although it didn't get fully dark it was pretty interesting and the birds were very confused. Also, if I didn't do an eclipse map now I might never remember again. The next total eclipse in the UK isn't until 2090 and I just get the feeling I won't be on here making animated gifs of it then.

Notes: mapping software was QGIS 2.14, using the Atlas function to extract the frames for the gif. I used the NASA shapefiles to show where the path of totality and centre line are. I added some place names, roads and US boundary and state lines from Natural Earth and I also added an ESRI shaded relief base layer to give more of sense of the underlying physical geography. I patched the gif together in GIMP and animated the movement of the sun across the land using the vertices of the eclipse centre line. I've added a little glowing corona round the black dot, which is of course supposed to represent the sun.

There were about 1800 points in the original NASA eclipse path file so I used every second one to generate the animation because it still creates a reasonably smooth image. For a proper set of scientific maps, I suggest you check out the NASA Total Eclipse pages, as they are full of great information and maps. They also have an animated gif.