base map
From Glossary of Meteorology
A map designed for the presentation and analysis of data; it usually includes only the coordinates, geographical and major political outlines, and sometimes the larger lakes and rivers.
Many modifications exist for specific uses throughout the geophysical sciences, such as the frequent inclusion of fixed reference points (or station positions). Mountains and contour lines are generally omitted, but high ground may be indicated by a single contour line and shading.
