QGIS 4 Install and data
Let’s get started.
QGIS install
Get QGIS 3 installed. You could follow instructions. If you’re on a Linux, packaging is fast. The usual failures of packaging are that the package is not up‐to‐date, and that installation of extensions is poorly documented or crippled. But QGIS is mature software, I have no need of extensions, so I used a package.
QGIS is KDE/Qt desktop software. This will require extra software on a Gnome desktop, and will at times misbehave. But this is how I use QGIS. I already have the extra software installed. The misbehaviour is acceptable.
Refs
QGIS site (English),
QGIS, Wikipedia,
Get some map data
Finding map data is not easy. For this tutorial I say,
Data is OSOpenData. VectorMap District. These maps are of the UK. They are licenced in a way compatible with Creative Commons. The data is vector data, and contains mid‐level detail with multiple layers
The maps need to be downloaded per tile. There’s over 50 tiles for the UK, so pick some
Download as Shapefiles
Once you have downloaded, put the data somewhere categorised and named. QGIS will work from the data directly, not load into memory. If you leave it in a temporary or download location, if the data is moved or deleted, projects will fail to load.
Other maps
Maps are available from several sources. Some organisations release maps for free, for example, the British Ordnance Survey (which I suggest above). The organisation releases many basic map‐data sets which are supplied under an attribution licence. Some maps are available only for money. Or you may choose to get map‐data from a supplier. The data may not be free, but the supplier will have worked to, for example; crop by area, source the best available data, provide consistent map‐data sets, and apply startup styles. This, as you will see in this guide, is a huge amount of work so you may he happy to pay.
If you get into this world, there’s a whole area of QGIS functionality I skip. QGIS, as shown in this tutorial, can load map data from a huge range of formats. When I say that, I mean load data from a local computer. But QGIS can also act as a server, which means it can talk to online resources then download information. For example, if you would be interested in map‐data from the free OpenStreetMap project, this is how to do it. But that involves also QGIS plugins…
Refs
Map supplier who provides province maps by country or world,
Ten free map‐data resources. Aside from immediate use, illustrates how diverse the sources are,
https://gisgeography.com/best-free-gis-data-sources-raster-vector/
A coherent discussion of the free map‐data available from the British Ordinance Survey. This kind of coherent usable discussion is rare,
Tutorial on downloading OpenStrretMap data. Requires plugins,
https://www.qgistutorials.com/en/docs/downloading_osm_data.html
(if possible) Get some style data
The UK Ordnance Survey provides supplementary styling material for their map data. You’ll need it—no way can you style an OS dataset, not unless you have a month of spare time,
Goto https://github.com/orgs/OrdnanceSurvey. Find your best guess for which extra material may work for you. This is not easy, with anything up to 100 repositories to choose from, many automatically‐generated and empty READMEs, and no overall guide or index. I suggest ordering the repositories by popularity. If possible filter by the kind of file you are looking for
We’re looking for QML files, for use in QGIS, for VectorMapDistrict data, so the repository is probably (currently) https://github.com/OrdnanceSurvey/OS-VectorMap-District/. Download the repository
If you find a style file repository, you’ll be following the instructions included there (if there are any).
(Optional) Get a coordinate transform
I talked about coordinate systems in the last section. If you know what you are doing, or are following this guide closely then, while we are setting up, we may as well download a coordinate transform.
The data I suggested to download for this guide was Ordnance Survey VectorMapDistrict. This data uses the coordinate system ‘British National Grid 1936’. My version of QGIS did not have an up‐to‐date transform for this system, So I downloaded from https://download.osgeo.org/proj/proj-datumgrid-europe-1.5.zip. You need the file ‘OSTN15_NTv2_OSGBtoETRS.gsb’. Please bear in mind I can’t guarantee this link. The transform will be changed every five years or so. Also, at the time of writing, the British National Grid is moving to a new transform standard. Best I can tell you is that this was the transform for Summer 2022.
If you don’t know the coordinate base or transform you need, don’t be concerned. QGIS has an outstanding system for identifying and installing transforms. But you will need to wait until you load map data, in the next steps of the guide.
End of install and data downloads
Not finished. This may be specific to the guide data, but we need to setup styles