This blog post I wrote for Locate Press helps set the stage for those new to the scene of mapping, geography, spatial data, and application development.
Category: Geospatial
Getting into large(ish) GIS datasets
It’s been a long time since a post but I wanted to highlight some of the new tooling that I’m learning while digging into the OmniSci platform – namely, extreme geospatial map rendering and analytics powered by server-side GPUs.
In this video I load a ~12M point dataset from geonames.org and explore it using both QGIS and OmniSci – just to get a feel for how easily it fits a normal kind of GIS exploration workflow.
See OmniSci in action with truly large datasets (we talk in billions usually) using some interactive demos at: https://www.omnisci.com/demos
Deep learning + cartography
A couple years ago you may have read this great post from boredpanda talking about a research paper that took deep learning algorithms and applied them to art. This opened up the possibility of, say, taking a photo and having it re-imagined as being a painting from an old master.
It’s actually pretty easy to do this now using a site called deepdreamgenerator.com. I’ve done quite a few experiments on the site using a variety of images from the web and found it pretty fun.
I’ve also started to download some of the deep learning toolkits (e.g. Berkely Caffee) that are available, hopefully I can do higher resolution work with these in the future.
But for you today I thought I’d take a basic QGIS map using Natural Earth dataset and have it “re-cartofied” as Mercator – and show you how I did it.
Step 1 – Make a world map with QGIS
Using the awesome data from the Natural Earth website I put together a very simple world map.
Step 2 – Grab an old map
The way this deep “dream” imaging site works is that it can use a second image as, what they call, a style. So I first just grabbed a basic Mercator map of Scotland. Lots are available on David Rumsey’s awesome map library site!
At first I used the full basic image without any processing, but it produced weird artifacts – lines, etc. in the resulting map. Here are a few of my test images. If you select them from this page you can see the input/source images.
Step 3 – Deep Learning Cartography Magic – Voila!
The final version of my map turned out good enough, though there are several more settings I could tweak. Note, those are not compression artifacts – they are mountains! Yes, in the ocean 🙂
Tips…
To get this far I had to also crop the Mercator source map to remove page borders, legend, surrounding text, etc. This helped reduce the set of input style items to things like mountains, water, and of course CASTLES! 🙂 Here is the image I used for styling.
I hope you found this interesting, if you make something similar please share it with on Twitter/1tylermitchell.
Make Stellar/Star Data Maps In GIS
I have a latent interest in stargazing but haven’t done much about it for a long time until the past weekend when I had a bit of time and wondered if I could create a star map using QGIS. I found a couple tutorials and stackexchange questions that referenced David Nash’s HYG Database from www.Astronexus.com. Some of the tutorials showed equations for computing latitude and longitude from the star position values – ascension, declination specifically. However, I found that there is already an X and Y column in the latest version of the dataset which makes it easy to map, here’s how.
Download the Star Location Data
From the HYG Database page, grab the HYG version 3.0 dataset:
- HYG 3.0: Database containing all stars in Hipparcos, Yale Bright Star, and Gliese catalogs (almost 120,000 stars, 14 MB)
The resulting 34MB CSV file contains about 20 columns and 119,615 rows.
Import CSV File into QGIS
- Launch QGIS (I’m using 2.10.1-Pisa)
- Select Layer -> Add Layer -> Add Delimited Text Layer
- Browse to the file location, select File Format radio button as CSV and the rest should take care of itself
Tweak the Map
If you use a typical WGS84 projection you’ll get a ton of points oriented in a circle. I took a few minutes to zoom into a meaningful scale (for me it was around 1:5M), change the background colour and then use the LUM attribute to change the relative size of the stars. I also changed the colours to be shades of white. Here is what I was able to produce. It’s not all that meaningful to me but I know that when I need to dig into the data further it will be available!
I’ve attached my project file here so you can get started quickly.
I’d love to hear what you would use this kind of data for and if you have any tips for making it more useful or better rendered.
