Compilation

Sketching and drawing

Early in your process, move between hand-drawn sketches and data-driven drawings of your layout.

Design involves reflective action. You try something and then critically evaluate how well it works. In graphic design, the process involves externalizing ideas in your head so that you can react to them. Sketching facilitates this, because you can quickly generate a set of alternatives for any single problem and then select the alternative that works better than others.

Drawing in cartography (often done by using a GIS to plot data at scale) is a slower process. It takes longer to generate alternatives and GIS interfaces tend to add cognitive load that can impede creative flow. Yet you cannot ignore your data, because it brings many constraints – quality, distribution, etc – that will affect your design.

If your workflow involves moving from a GIS (where you compile your data) to a graphics program (where you style your data), you will also need to make some important decisions early in your workflow that are costly to change later. This includes choosing a scale, extent, and projection. Ideally, you want to avoid spending a lot of time and effort styling your data only to realize that your projection could work better, or your extent is not quite right, or you regret your scale.

To help with this, get in the habit of moving between sketching out your ideas by hand and drawing out your ideas with a GIS. Good design generally emerges as a dialect between these two actions.

Map projection

What projection did you use and why did you decide to use it? This question largely pertains to smaller-scale maps (large area, small map) where your map will necessarily distort some qualities of space due to the projection that you choose. Consider the needs of your map reader: will they need to infer or compare the area, shape, distance, direction of features on your map? If so, what projection would help them do this?

Map scale and extent

Did you consider how the size of your region of interest, the amount of paper or monitor screen you have to work with, and your purpose for selecting and styling map elements influence your choice of scale? Did you make the scale (or representational fraction) a round number and something that easliy scales for measurement or reasoning about distance? (For example, on 1:62,500 scale, 1 inch equals 1 mile).

Select with purpose

Anything that’s on a map that doesn’t need to be there is just going to distract the reader or compromise the clarity of a map.

Select only those aspects of the world that are necessary to support the purpose of the map and fulfill the needs of your map user. Ask yourself these questions:

Do you show appropriate (not excessive detail) of area and line features for your geographic scale?
Have you selected reference features to support allocentric referencing (location of one feature with respect to another feature) without making the background too visually noisy?
Is there anything on your map that attracts attention without contributing to the purpose of the map?

Simplify linework

If you use GIS data for linear features, the data may be more precise than necessary for your map’s purpose.

Simplify features that show lines (polylines and polygons) so that vertices do not pile up on each other and create the appearance of blotches and fills. When you simplify, take care not to distort the topology or topography of the geographic features.

For example, be careful not to transform narrow but deep bays along shorelines into inland lakes. When simplifying line features, preview the changes before you make them and focus your preview extent on an area of the map with features that are susceptible to distortion, like narrow bays on a shoreline. Choose the appropriate balance that simplifies the feature without distorting topological or topographical properties.

Reference features

People think about space more in relative than in absolute terms. It often feels more intuitive to think about the location, size and distance of something relative to something else, rather than the exact x,y,z location of something.

Do you have some features on the map that help people locate the things that you are trying to emphasize (to help them understand where features are in your geographic region)? Have you supplied just enough of these features to serve as references without cluttering your map?

Clarify relative locations of map features, even if this requires you to alter the absolute location of features. For example, it a road follows a river, make sure the road does not appear to touch or overlap the river due to the scale of your map and the precision of your line data.

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