Map Terminology

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The science of measuring water depths to determine bottom topography.

A cadastral survey relates to land boundaries and the definition of ownership, limitations of land titles, etc. Derived from “cadastre” meaning a register of land quantities, values, and ownership used levying taxes, the term may properly be applied to surveys of a similar nature outside the public lands, such surveys are more commonly called “land surveys” or “property surveys.”

The science and art of making maps and charts. The term may be taken broadly as comprising all the steps needed to produce a map: planning, aerial photography, field surveys, photogrammetry, editing, color separation, and multicolor printing. Mapmakers, however, tend to limit use of the term to the map-finishing operations, in which the master manuscript is edited and color separation plates are prepared for lithographic printing.
Center fold

Chart, nautical:
Representation of a portion of the navigable waters of the Earth and adjacent coastal areas on a specified map projection and designed specifically to meet requirements for marine navigation. Included on most nautical charts are depths of water, characteristics of the bottom, elevations of selected topographic features, general configurations and characteristics of the coast, the shoreline (usually the mean high water line), dangers, obstructions and aids to navigation limited tidal data, and information about magnetic variation in the charted area.

Report maps vs Charts:
Special-purpose map designed for navigation or to present specific data or information. The term “chart” is applied chiefly to maps made primarily for nautical and aeronautical navigation, and to maps of the heavens, although the term is sometimes used to describe other special-purpose maps.

Index Map:
The index map appears at the beginning of an atlas or of a series of maps, and is used to indicate where in the atlas you can find a map of a certain area.  It can be used much like a table of contents in a reference book. But don’t be fooled by their usefulness- index maps are also decorative and enjoyable to have on your walls!

Inset Map:
A smaller map or chart inset within a larger map or chart that shows greater detail of an area on the chart.

Plate Mark (also Plate Impression):
The platemark is a rectangular impression with rounded edges made in intaglio printing when a metal printing plate is pressed firmly into paper.  In this type of printing (sometimes called etching) the paper is slightly damp and a significant amount of force is applied using a printing press.  A plate mark can help you identify an antique versus a reproduction, but beware- it is possible to fake a platemark!  Trained eyes can usually spot a fake, which is why it is wise to have a valuable map appraised by a professional.

Recognition Profile:
A view of an area as it would be seen from the water, and including any noticeable landmarks, like churches, lighthouses, rivers, and more. These are often included on nautical charts in order to help sailors recognize what part of the land they are looking at.

A technique for establishing the distance between any two points, or the relative position of two or more points, by using such points as vertices of a triangle or series of triangles, such that each triangle has a side of known or measurable length (base or base line) that permits the size of the angles of the triangle and the length of its other two sides to be established by observations taken either upon or from the two ends of the base line. (from
This technique can be seen in many survey and report charts. Note the many straight lines used for triangulation in harbor areas.

Ward Maps:
A ward is a local authority area, typically used for electoral purposes. It is common in the United States for wards to simply be numbered.  Ward maps are maps of individual wards, published in an atlas showing all of the wards of a particular city.