Using Presets, Multiple Styles, Atlas With Overview Map – Lutra Consulting
Our training courses are structured to give trainees step-by-step guide using the latest QGIS features. Here is an example of one our practicals for creating professional maps. QGIS’ Print Composer allows users to create professional maps for printing. It supports legends, frames, logos and all the other features you’d expect to see in a print quality map. In this example, we’ll use some of the most common features required to generate a map for printing. We’ll first load the electricity usage data created in another tutorial, style it using a simple colour ramp, then create a new map composer complete with title and legend. The styling of a vector layer can be performed using a single style, or a varying style, based on the value of one or more attributes. We are going to first load the London energy usage layer prepared in an another tutorial by joining electricity usage with the LSOAs vector layer. In QGIS, you can apply multiple styles to a single layer. Using this method, we do not need to load the same layer multiple times. In this case, we need two styles for London boroughs layer: We’ll now add labels to each of the boroughs. The name of each borough is stored as the value of the NAME attribute. This window will allow us the set an attribute for label and also change font, size, rotation, buffer, etc. In QGIS, you can create presets for layer visibility and styles. In this example we are going to create the following presets: A separate preset for the London boroughs (without labels) which will be used as an “overview” for the print composer To ensure the preset has been correctly set, you can change the visibility of the layer, or change the style, and select the preset from the Manage Layer Visibility menu. Now you should be able to switch between those two presets, and later use them as print composer frames. The map is almost ready to be printed. Before printing, we’ll need to add a border, logos, legends, scale, etc. There are quite a few steps involved in configuring the print composer so it’s recommended to regularly save your progress by saving the QGIS project. The print composer is split into two sections. Section 1 shows the map to be outputted and section 2 shows the settings for selected items in section 1. Now we need to add frames for the map extent and legend sections. You can add a rectangular shape by clicking on from the main toolbar. A scalebar with default settings should appear on the map. See Figure [PrintComposerAddScalebar]. To change the scalebar: QGIS will automatically add a legend for all the layers loaded in the canvas. We can edit the legend’s settings and remove the legend entries that we do not want to show. Manual edits of the legend text can also be performed to make it more readable. To be able to edit the legend items, you first need to untick the box for Auto update. Use icons under the Legend items to edit or change the order of the items. The map is now almost ready. You can export it as PNG or a PDF. Or you can keep reading for even more excitement! The map is now ready to be printed or outputted as an image. But, we are going to use this layout as a template and auto-generate energy consumption for each borough. You can change the Margin around feature if you like, but we can keep at 10%. Further settings are also required: The expression for output will set the name of each output file. In this example we are going to have a name with ‘energy_’ combined with the value of NAME column (what do you think this value is?) The process may take a while but you will eventually have 33 maps of the energy consumption for each borough. Note the overview for the maps and also the naming of the output files. See Figure beloq as an example of the maps created. Source.