Join Gordon Luckett for an in-depth discussion in this video Overview of QGIS features, part of Learning QGIS.
- Understanding the components of QGIS help to guide you through the install process and use of the product. We will explore all the components of QGIS for data collection, analysis, mapping, and the sharing of data. When you install QGIS, you get two products, the QGIS Browser, and the QGIS Desktop. Let's look at the QGIS Browser. Inside the QGIS Browser you could look at the directories to see the data files. For example, under Exercise Files, there are shapes. We could pick on Bike Routes, look at the metadata here.
You could see there's 494 lines inside of the Bike Routes. We could preview the graphics. We can zoom in by rolling our mouse in and out. And we could look at the Attributes, all the data inside of the shape file. I could also click on Parcels. This will show all the Attributes inside the Parcel shape file. I can preview the graphics, and I can look at the metadata. We can also look at raster data, so if I go into the Raster file pick on one of the ECWs, you can see that's a (mumbling) compressed wavelength file, see what location it's at.
You can see there's no layer spatial references assigned, but that's okay, I know it's in UTM Zone 10. If I hit Preview, I can zoom in and look at the Raster. There's also DEM files I can preview, and that will give me a grayscale version of the DEM. I can also look at the metadata. So there's a lot of information I can see right here in the QGIS Browser. I'm not able to edit any of this data, but I can view it, and preview it. There's other types of data you can connect to. There's MSSQL, which is Microsoft SQL server.
There's Oracle, PostGS, and SpatialLite. All forms of spatial data, but stored within databases. To connect to them, simply click on the MSSQL, or any of the others, and click New Connection. You can put in the Name of the connection, the Provider, the Host URL, and the Database you want to connect to. Now this is true for all of these, whether it be Oracle SQL server, PostGS, or SpatialLite. All the open web services are available, too, including WFS, and WMS. For example, WMS, we can have a precanned one already connected for NRCAN.
I can go to Toporama and pick on the boundaries. You can see all of the metadata for that connection. And if I hit Preview, you could see the boundaries being streamed directly from the NRCAN site. Although QGIS Browser can't edit or delete any data, we can make a new shape file from scratch. This allows us to create a new shape file and assign all the columns inside the shape file. If you want to put data inside of it, we would need to use QGIS Desktop to do that. Let's close QGIS Browser, and open up QGIS Desktop.
Let's add some of the data we were just looking at in QGIS Browser. First thing I'm going to do is add that boundaries from the NRCAN. There's the boundaries from NRCAN. Let's also go up to our Exercise Files on the desktop and add a couple of the shape files. For example, I may want to bring in the Bike Routes, and the Buildings. I'm going to right click on Buildings and zoom to that layer, there they all are. And we can zoom right in and I can pick on any of those and look at the data behind it.
You'll see Identify Results at the bottom here. See, that's Residential, and it's Area. I can also edit data by simply highlighting the layer I want to work on, I'm just going to clear the Identity results, I'm going to highlight the buildings, I'm going to click on the Edit button, and you can see all the tiny Xs, those are the grips I can edit data with. But I also can draw a new one, so for example, I can draw a brand new polygon right here and draw a brand new building, and say it's a Shed, and it's one story high. There you go, I draw a new shed.
Now all I have to do is click Stop editing, and I can either Save it or Discard it, I'm going to discard it for now. But there you have it. So you can add data directly. Let's add a Raster layer, as well. So I'll bring in one of the ECWs, my notes in Zone 10 UTM, so there it is. And I'm just going to zoom to it really quickly and put it behind some of the other data, there we are. So now we've got Raster data connected to our QGIS session. We have Bike Routes, we've got Ortho Photos, Buildings, all sorts of things.
And you saw you can edit data. Now there's a lot of other things we can do. Within the Vector dropdown there's a lot of geometry tools, and analysis tools. We can do geo-processing, overlay two vector layers, make a buffer, intersect, union. With Raster, we can do all sorts of things like we can convert things, such as translate from one format to another, from ECW to TIFF, and so on. We can extract contour lines from a DEM file. We can connect the databases. There's a lot of processing tools, as well.
On top of all of that, we can publish maps, and create maps, using our print composers. So if you make a new print composer, you can add your map to the current session. So you could go like this and add a map, and print it and set up your plots and that sort of thing. So the print composer's there for plotting. There's a lot you can do inside of QGIS Desktop. You have learned about the key components of QGIS, and what tools you have at your disposal to create data, maps, and to share your information.
- Explain how to determine if you should install the 32-bit or 64-bit version of QGIS on a Windows 10 machine.
- Write the command that will navigate you to the "Add WFS Layer from a Server" dialog window in QGIS.
- Identify what format WMS typically delivers images in.
- State which layer properties tab allows you to edit the line layers of a shapefile.
- List the labels tab that should be selected to edit the visibility of vector data labels at certain scales.
- Identify what programming language the OpenLayers plugin is written in.