Text on maps
The purpose of text on maps
Labels or names on maps can have multiple functions: to provide a location, to provide identification of features, or to provide other additional information to the user. Names can be proper names such as the official names given to places or they can be descriptive names such as hospital, pub or parking. What labels are included on a map will depend on the requirements of the user and the purpose of the map. When deciding what labels to include, think carefully about what might help the user to understand the message of the map or to orientate themselves in terms of where the area of interest is.
Text design
Text can add meaning to a map and help the user quickly differentiate between different feature types (e.g. rivers vs settlements) or between features of the same feature type (e.g. settlements) but of varying size or importance. This can be achieved by carefully changing the characteristics of the text.
Text placement
The placement of text can be one of the trickiest parts of making a map, or any data visualisation for that matter, particularly as automatic labelling engines in many GIS don’t do a great job. It is often the case that labels need to be placed manually, either within the GIS, or in a separate graphic design programme.
There are a few general best practice rules around text placement on maps:
Legibility is key – there is no point in adding text if it can’t be read. In order to maximise legibility, it is advisable to try and avoid placing text over map detail as it can make the text hard to read. If covering detail is unavoidable, a small text halo or mask can be included to help with legibility.
Labels must be placed so that there is a clear, unambiguous link between the label and feature it represents. To achieve this, it is important to place the text such that there is not another feature between the text and the feature it relates to. Further best practice for label placement for different feature types is discussed in more detail below.
Text should generally be oriented horizontally and should be readable from the bottom of the map (not upside down). Exceptions obviously exist where text is curved or diagonal along linear or aerial features or curved to follow the lines of the graticule. These exceptions are discussed further below.
In addition to the general best practice, there is specific best practice when it comes to labelling point, line and area features.
Point, line and area features
When labelling point features, the text should ideally be positioned just above and to the right of the feature it is representing. If positioning the label in this location results in the text sitting over detail, or results in conflict with another label, a sequence of positions should be considered. If the top right is not appropriate then the bottom right, top left, bottom left, top centre and then bottom centre can be assessed in sequence. The least preferrable location for labels is directly to the right or left.
The position of labels for point features should also be considered so that they enforce location, particularly in relation to linear features. For example, the label for a town located to the west of a river should be placed to west of the river to enforce this spatial relationship. The same goes for any boundary line, not just a river. When naming point symbols along the coast, towns which are actually on the coast should generally have their names in the water for legibility reasons. Inland towns should have their labels entirely on land. Placing names so that they straddle land and water should be avoided for legibility and aesthetical reasons.
Linear features include physical features such as rivers, roads and railways but also include theoretical lines such as borders and the equator. Text for linear features should generally be placed alongside and parallel to the feature but not touching it. Text for roads and rivers, if there is space, can be placed within the feature but should not cross junctions with other rivers or roads to avoid confusing the user. When labelling isoline features such as contours, the line should be broken to accommodate a label.
Ideally, a relatively horizontal or gently curving section of the line should be chosen and the name placed on a gentle curve which mimics the curvature of the feature. Complex curves should be avoided as the text becomes difficult to read. If a feature is vertical (or near vertical) the label should be placed so that if the text were to fall flat, it would not be upside-down.
Labels along particularly long linear features may need to be repeated to help user understanding. The repeated labels should be spread along the feature at suitable intervals and are often placed above or below large tributaries or road junctions to help the user follow a feature along its length with ease. This re-labelling approach along linear features is preferred to the exaggeration of letter spacing to show the extent.
Area features include features such as woodlands, mountain ranges, lakes, oceans and counties. If the feature is large enough, the label should be placed within it and the spacing between the letters increased so that the text is spread out across the area to show its lateral extent. The text can be rotated and curved slightly so that it follows the long axis of the feature or can be placed horizontally – both approaches are fine but it is best practice to keep the labelling approach consistent across your map. Care must be taken that the word does not get so extended that it becomes impossible to read as a single word. One exception to the letter spacing is where linear features are aerial in nature, such as a river. In these situations, the text should be placed within the river but should use normal letter spacing so that they are legible. Small areas may need to be labelled as point type features.
If you’re looking for more information in the placement of names, Swiss cartographer Eduard Imhof’s 1975 paper titled ‘Positioning Names on Maps’ (originally published in German) is a good place to start.
Making text legible
As we’ve already mentioned, legibility is key when including text on a map or data visualisation. When designing your text, consider the colour of your label vs the colour of the background. If the contrast between the two is low, the text will become hard to read. Increasing the contrast between the background and the text can help this. More information on the use of colour can be found here. The use of masks and halos around text can be a great way of making text legible, particularly where there is detail underneath the text. However, care must be taken to ensure that the halo or mask isn’t so large that it covers crucial detail beneath it. Finally, if space is tight and there is a risk of covering crucial detail or another label, leader lines can be used to aid legibility.
Read more about ways to make your data visualisation accessible here.
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