Geoscientific communication often includes spatial presentations of study areas. Such maps often display a wealth of information that immediately informs an audience of the geoscientific setting involved in the presented research. Maps may show the outcropping lithologies in an area, or they may highlight locations that samples were collected from, where analyses were done, measurements were taken, etc. For the reproducibility of scientific findings, it is important that such maps adhere to certain requirements. This way, the audience of your presentation or reader of your text can verify your observations, either through satellite imagery or in the field.
In general, maps require:
- A metric scale: in m or km, depending on the size of your map.
- Spatial reference: Always include a coordinate system and north arrow, and mention the geographical/projected coordinate system used to display your maps (e.g., WGS 84 or others).
- Legend: must include all features on the map, e.g. coloured/shaded areas, symbols etc., including the units of values you may be presenting.
- Appropriate symbology and colour use.
Apart from these basic requirements, maps often include:
- Abbreviations and annotations that indicate names of mountain ranges, rivers, towns, etc. All abbreviations are explained in the figure caption, rather than in the legend.
- Insets of larger scale maps highlighting the regional/global tectonic setting, or other valuable information that cannot be included in the main map.
- Base maps, i.e. satellite imagery, terrain, hillshade, or slope maps that add a three dimensional or spatial perspective to the mapping presented on top. Choose the type of base map you use consciously and with its purpose in mind. Note that for the base map to increase value of the presented map, top layers such as shaded areas and other map projections need to have partial transparency.
Remember to always make maps with a purpose in mind. Consider what it is that you want to communicate and decide what the bare minimum of information you need to include to convey your message is. Avoid including all available information of a certain area in your map, but consciously and critically select the map layers necessary to inform your audience as efficiently as possible. For an example of a clear and targeted map, see Fig. 2 from this paper by Walk et al. (2020).