What feature does a conformal map projection preserve?

A conformal map projection is specifically designed to preserve the shape of small figures, which is a critical characteristic for applications in navigation, aeronautics, and other fields where maintaining angles and local shapes is essential. This means that although the overall scale of the map may distort larger areas, the angles around small regions remain accurate, allowing the true geometric relationships within those areas to be represented correctly.

For instance, if you were to draw a small triangle on a conformal map, the angles of that triangle would remain as they are in reality. This property is what makes conformal projections particularly useful when precise shapes and angles need to be analyzed or when working with detailed designs or engineering projects.

In contrast, while other types of projections might preserve area or distance, they do not maintain the accuracy of shapes at a local level. Therefore, conformal projections are chosen specifically for tasks where the accurate representation of small shapes is paramount, making the preservation of the shape of small figures the defining feature of this type of projection.