Catalogue number: Catalogue number: 89200005
Issue number: 2020003
Release date: February 17, 2020
QGIS Demo 3
Loading and Ordering Spatial Data in QGIS - Video transcript
(The Statistics Canada symbol and Canada wordmark appear on screen with the title: "Demo 3 - Loading and Ordering Spatial Data in QGIS")
Hello everyone! So now that we've downloaded QGIS and spatial data, today we'll learn how to load and order datasets of different geometry types in QGIS, and save the Project for later use. For the demonstration we'll use several datasets that we downloaded in the previous video, covering the main geometry types of vector data: points, lines & polygons.
So the first step is to open QGIS Desktop from a desktop shortcut or from the start-bar.
And the first thing well do is pin QGIS to the taskbar since we will be using it frequently in subsequent training videos.
When you open QGIS for the first time it looks like this.
To load spatial data into QGIS, they are added from the Browser panel, in to the Layers panel, and also visualized in the Map Canvas.
So the first thing we need to do is expand the folders to find where we downloaded our spatial datasets to in the previous video. So I'll expand the Home folder and the Documents folder to find the GeospatialData folder.
Since it's the first time we're locating this folder, we'll right-click and add it as a favourite, which adds it to our favourites drop-down at the top, which will help us load datasets more quickly and easily in the future.
To see the available layers just continue expanding the folders, and within the Intro Demo folder there are 4 shapefiles and 2 geodatabase files.
So to load datasets in it is quite simple, you can just double-left click or drag-and-drop from the Browser to the Layers panel.
These procedures can also be applied to geodatabase files, you just need to expand the folder to see the available layers first. For Grain Elevators there is only one, so just double left-click, while for Transport Features there are many, but for the purpose of the demo we'll use the Road Segments layer.
Finally we will load in our two census boundary files into the layers panel.
Don't worry if the colours of your files differ from those in this video. QGIS assigns a single random colour when vector datasets are loaded.
So within the Layers Panel, individual layers can be toggled off and back on again, as well as renamed. So here I'll just rename the Census Subdivisions file with a more intuitive name.
Despite having loaded the six layers into the Layers Panel, we can only see one within the Map Canvas. This is because the order within the Layers Panel affects the order that they are rendered in the Map Canvas.
So in general points are placed above lines, which themselves are placed above polygons. For vectors of the same geometry type it is important to think about their position in the landscape relative to one another – so do rivers flow over roads, or do roads tend to get built over rivers? Well often roads are built over rivers, so we'll just switch their order in the Layers Panel. And similarly, the Lakes and Rivers polygon, as a land-cover feature we'll place it above the census boundary files.
So now if we zoom in we can see that all of our layers are visible in the Map Canvas.
The final component of the video I'd like to discuss today is saving the project for later use. This will save the order of layers in the Layers Panel, any visualizations styles such as labels or colours as well as any joins– all procedures that we'll discuss in later demos. So navigate to the Project Toolbar and click on the Save Icon. In general we want to store the project in the same location as the spatial data, and provide it with an intuitive filename, like Loading and Ordering Spatial Data.
So that concludes the procedures for loading datasets into QGIS from the Browser to the Layers Panel, which will work for most spatial data, and how to order them in the layers panel for their visualization in the Map Canvas. Additionally, we learned how to save our project and the specific properties that are retained. Stay tuned for the next demo, where we will explore some of the tools on the Map Navigation and Attribute toolbars for interacting with these datasets in the Map Canvas.
(Canada wordmark appears.)