Today I’m going to do a thread on something I want to learn more about but have used a little in the past. So be warned this topic might not be 100% accurate but is my understanding. Interferometric synthetic-aperture radar or InSAR for short because everyone loves acronyms. Its a way of measuring how much something has moved between two radar “images” the something can be a building, a dam, a mountain....

Today we’ll talk about ais data. This is another post that started out as a thread over on mastodon Sorry it’s another acronym. Automatic Identification System. It’s original purpose was for ships to be able to tell each other where they are and which way they are going to avoid collisions. It is a little radio box on the boat that sends periodic messages saying “my Id is 123456, I’m at this lat and long, I’m going this way at this speed” it also sends out other messages like “my Id is 123456 my name is see the wind, I’m a bulk grain transporter and 30m long”...

Today’s topic: NDVI. This is another post that started life as a thread over on mastodon. What the heck is that? It’s an acronym (sorry) it stands for normalized difference vegetation index. Short version it’s a proxy for how much healthy plant life there is. It will be a number between -1 and 1. -1 being a clean concrete slab or similar. 1 being an impossibly healthy rainforest canopy. The way this one works is comparing the difference between absorption of near infrared light and red light....

Note: This post started out as a thread on mastodon. Please follow me there if you’d like to see this sort of thing early Lets start talking about something I wish I didn’t know as much about as I do. The 180 degree line! +/-180 degrees longitude. It is not the same thing as the international date line, that’s defined politically which lots of wiggles through the pacific islands. The 180 degree line only crosses two countries, Russia and Fiji....

Hi. My name is Emily. No I’ve not taken over this blog for the day. I’m still the same author but a while ago I came to realize I’m a woman so my old name didn’t fit any more. Don’t panic I’m still doing mostly the same things as before. Just with less background noise in my head so things are a lot better. Family, friends, and colleagues reading this Waves....

A little while ago I found my self needing to be able to parse screen resolutions when generating some images in a golang program. I created a library to do this and had a bit of fun optimising it. The result is open source on github. It is a very simple library with a single function but I thought it might be interesting to walk you through the process. What we need to build is a function that takes a string like “1080p”, “800x600”, or “4K” and returns a width and height value....

I’ve been using the Windows Subsystem for Linux (WSL) for a while at work. It’s been something of a radical improvement over cygwin for most of my use cases. A couple of weeks ago my installation got borked by the work Antivirus (AV) system. So I’ve created an automated script to set up my environment just how I currently like it. Before we start lets get one thing out the way....

A little while ago I attended the Climathon kic event/hackathon in Bristol at my old university. The event was to come up with solutions that could help with pollution in the city. There were not a lot of people who turned up so we formed a single team. The idea we came up with was to create an incentive for people with flat roofs to put plants on them. This meant we needed to be able to find flat roofs in the city....

In the last post we read the minor planet center observation file. This was a fixed width text file. We only pulled a couple of columns out of it, but we learnt to use User Defined Functions, groupBy and select. In the first post of this series we covered reading a json file which contained information about all the asteroids we know about. This time we are going to join the two data sets together and finally solve our original problem, which was to find the full date of the earliest observation of each un-numbered object....

In the last post we read the minor planet center orbit file. This was a JSON text file. This time we are going to look at a bit more complex file to process. If you haven’t read the first post in this series I recommend starting there before reading this. In this post we are going to be looking at the Observation file. There are two parts to this file. One is for the numbered objects and other other for the un-numbered objects....