How do you communicate the limitations and assumptions of map projections to your clients and stakeholders?

1 Choose the right projection

The first step in communicating map projections is to choose the right one for your project. Different projections have different advantages and disadvantages depending on the type, extent, and location of the area you are mapping. For example, conformal projections preserve the shape and angles of features, but distort the area and distance. Equal-area projections preserve the area of features, but distort the shape and direction. Azimuthal projections preserve the direction from a central point, but distort the shape and area. Cylindrical projections are suitable for mapping large regions near the equator, but distort the poles. Conic projections are suitable for mapping mid-latitude regions, but distort the edges. You should select the projection that best fits your project's objectives, requirements, and specifications, and explain why you made that choice to your clients and stakeholders.

2 Explain the distortion

The second step in communicating map projections is to explain the distortion that occurs when you project the earth onto a map. Distortion is inevitable and unavoidable, but it can be measured, quantified, and visualized. You can use tools and techniques such as scale bars, graticules, Tissot's indicatrices, and distortion grids to show how much and where distortion occurs on a map. You can also use examples and analogies to illustrate the effects of distortion on features such as continents, countries, islands, lakes, rivers, roads, and buildings. You should explain how distortion affects the accuracy, reliability, and usability of your maps, and how you minimize, compensate, or correct for it.

3 Acknowledge the assumptions

The third step in communicating map projections is to acknowledge the assumptions that underlie them. Map projections are based on certain models, standards, and conventions that simplify or approximate the complex reality of the earth. For example, most map projections assume that the earth is a perfect sphere or ellipsoid, but in fact it is an irregular geoid that varies in shape and size. Some map projections use a common datum or reference system, such as WGS84 or NAD83, but others use a local or regional datum that may not match with other maps. Some map projections use a common coordinate system, such as latitude and longitude or UTM, but others use a custom or proprietary coordinate system that may not be compatible with other maps. You should acknowledge the assumptions that your map projections make, and how they affect the consistency, compatibility, and interoperability of your maps.

4 Provide the metadata

The fourth step in communicating map projections is to provide the metadata that describes them. Metadata is the information that documents the source, quality, and characteristics of your maps. It includes details such as the name, type, and parameters of the projection, the datum and coordinate system used, the scale and resolution of the map, the accuracy and precision of the data, the date and time of the survey, the methods and instruments used, the standards and regulations followed, and the limitations and uncertainties of the map. You should provide the metadata in a clear and accessible format, such as a table, a report, or a digital file, and make it available to your clients and stakeholders. Metadata helps them to verify, interpret, and use your maps correctly and confidently.

5 Educate and inform

The fifth step in communicating map projections is to educate and inform your clients and stakeholders about them. Map projections are not just technical or mathematical concepts, but also cultural and political ones. They reflect different perspectives, values, and interests of different groups and individuals. They can influence how people perceive, understand, and represent the world. They can also have implications for decision-making, planning, and management of land and resources. You should educate and inform your clients and stakeholders about the history, diversity, and significance of map projections, and how they affect their goals and interests. You should also encourage them to ask questions, provide feedback, and share their opinions and preferences about map projections.

6 Communicate effectively

The sixth step in communicating map projections is to communicate effectively with your clients and stakeholders. Communication is not just about transmitting information, but also about building rapport, trust, and understanding. You should communicate with your clients and stakeholders in a way that is clear, concise, and relevant. You should use appropriate language, terminology, and tone. You should avoid jargon, acronyms, and technical terms that may confuse or alienate them. You should use visuals, graphics, and examples that illustrate your points and support your arguments. You should also listen to their needs, expectations, and concerns, and address them promptly and respectfully. You should communicate with your clients and stakeholders throughout the project, from the initial consultation to the final delivery, and follow up with them after the completion.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?