A map is a means to communicate information (as well as new ideas) to the audience. We use symbology to convey the contents of our data so it can be easily understood. When we create a map layout, we go one step further - we present our map so that it becomes a means of information.
No matter what media we plan to distribute our map by (whether it’s printed or sent over the internet), we must pay attention to how the map elements are composed in the layout. In this module we will discuss the presentation of printed maps, and create our very own.
The QGIS Map Composer allows you to prepare your map for printing. Apart from the map, you are able to add additional information such as images, labels, legends and scalebars.
This map shows some familiar layers from the previous module. We have the roads and vegetation of Sleman, along with the three impact zones from a Merapi eruption model.
Let’s see how we can use Map Composer to adjust the layout and prepare this map for printing.
This is the window where you can compose the layout of a map that you want to print. The blank white area is your “canvas.” It is a model of the paper you are going to print out. You can put various elements onto this canvas, such as your map (obviously), a title, scalebar and legend. These are elements commonly used on printed maps.
Take a look at the right panel. In the Composition tab, you can change paper size, number of pages and quality of output.
Take a look at the icons across the top of the window. We will use some of these as we lay our map out, so here’s an overview of what they do:
|Add New Map will add a map element. This is what we will use to add the map from our project into our print layout. It should be noted, however, that if we change the map in our QGIS project, it will not update the same map that we have added to our print composer, as we shall see later.|
|Add Image allows us to add a picture. You can add a company or organisational logo, or simply display images from a particular location. You can also add an image of a compass (to point North).|
|Add New Label is used for adding text to the layout, such as titles or other information.|
|Add New Legend is for adding a legend, which will conform to the active layer in the QGIS window.|
|Add New Scalebar is used to add a scale to the layout.|
|Add Ellipse/Triangle/Rectangle is used to add one of these geometric shapes. For example, this might be used to indicate special areas or highlight things on the map.|
|Add Arrow is used to draw an arrow on the map layout.|
|Select / Move Item allows us to choose and move the elements that are in the map layout. With this tool selected, you can right-click on an element to lock its position.|
When you change the scale some parts of your map may become invisible. Click on the “Move item content” button and drag the map so that it is all visible.
Now we’ve got the most important thing added to our map layout - the map! But let’s add some additional elements to make it more informative.
Your map layout should now look similar to this:
Let’s add a scale bar, so that anyone who looks at our map will have an idea what size area this map shows.
This should result in a scalebar that looks like this:
Now let’s create a grid for our map.
We used coordinate reference systems with UTM (metre) on the project QGIS and all map layers.
Play around a little bit with the coordinate format. You can change decimal degrees as the coordinate format or change it into Degree Minute format (DD MM) or Degree Minute Second (DD MM SS).
You can also adjust the coordinate placement. You can place the text inside or outside the frame, and make the orientation either vertical or horizontal.
Change the font type and font size by clicking Font in the panel.
Next, let’s add an inset that gives viewers of our map a little more information about what they are looking at.
The new layer will load.
Now let’s add a legend so that viewers of our map will know what our symbology represents.
To save your map composer that you created, you can click on the Composer ‣ Save Project. So if you open the project QGIS and want to use the map composer that you saved, click on Project ‣ Print Composer ‣ My Layout 1