like I did previously when the GHSL global population density dataset came out. This may of course be an anomaly so it's always worth doing a bit of a deep dive on any new dataset like this to check for values that don't seem right - e.g. The highest cell value I could find in the entire dataset was over 3000, which seems like quite a lot for a 30m x 30m cell. vrt layer.Īfter I did this, I spent quite a while panning, zooming, clicking and just getting to grips with the data. Here's what that looks like, including a screenshot of how I styled the population density. I added a couple of other layers, turned the background black and did a bit of styling - otherwise it would be a bit difficult to explore meaningfully. There are also some instructions from Facebook on how to load the data in QGIS.Īctually, I did explore this data after adding it to QGIS, but because it's just a black and white mess by default, I actually made it a bit nicer so that I could explore it properly. Notice that the upper value shown in the legend in the Layers panel will probably be way lower than the actual highest value in the dataset. When you add it to QGIS (it's about 1.2GB of tif files) you will see something decidedly unimpressive - but don't worry, that's easy to fix. If you don't see anything when you do this, it's probably because your tif files aren't in the same folder. vrt file directly into QGIS but you can also do it via the data source manager. I then open QGIS (I'm using version 3.10 right now) and then load the data. Note that as well as data on total population, you can also get a population breakdown by age. No matter what, this Facebook page takes you straight to what you need to know to download the data and start working with it in QGIS. For countries where you just have one tif file for the whole country you don't have to do this. vrt file in a folder and then unzip all the tif files into the same folder that the. The US data - unlike many other countries - is split into chunks, so the best way to get it into QGIS is to download the virtual raster file (population_usa_.vrt (16.1K)) and then download all the the files for the US that begin with ' population_usa18_' - there should be 32 of them if I've counted correctly.You can also get the data via the AWS open data registry, but I'm aware this is too technical for some people so I'll concentrate on the click-to-download approach.It's hard to know which data to download and how to work with it. And then I go to the results page for the United States - this is a good example to look at because there is so much data.
To get data for use in QGIS, I normally filter my search by looking for only Facebook data and in GeoTIFF format - here's an example search result, which returns 194 country datasets.Go to the Humanitarian Data Exchange (HDX) home page and search 'high resolution population density' and you'll get see lots of results - the data are available by country.Also, the data are available in more than one place but here's where I go to get it. Yes, this step is obvious but it's not always easy to remember where to find stuff on the internet so I'm putting this here for my benefit as much as anyone else. To save you a click: 'These maps aren’t built using Facebook data and instead rely on combining the power of machine vision AI with satellite imagery'. As you go further from the equator the cell size is of course smaller, but you can read more about the methodology here if you want to. At the equator, this is just under 31 metres square so that's very small areas. When I said 'high resolution' above, I mean one arc-second. Here's a couple of examples of the data for the New York City area and the San Francisco Bay Area - these show the general density patterns in 3D. I won't do analysis here but the basic workflow is simple - download it, load it, explore it, visualise it, analyse it.
It's one of the datasets I'm using in my upcoming QGIS and Aerialod training sessions so I've been working with it recently.
This is a brief introduction on how to work with Facebook's high resolution population density data in QGIS, for anyone who needs a bit of help getting started.