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Carto-Jargon 101: Cartography Terms Defined

The field of cartography is filled with jargon and terminology that can pose a challenge for newcomers learning to use mapping software such as MAPublisher to make beautiful maps, and those who don’t have a formal background in cartography. It also doesn’t make it easier when different software packages have their own variations on certain terms. To help the cause, we have compiled a short list of common cartography terms or “carto-jargon” that you may encounter while using MAPublisher or Geographic Imager.

Basemap

A basemap is a background image which can include aerial imagery, topography, terrain and streets and other fundamental layers and is used as a starting point to create a new map. The basemap is georeferenced and is usually the most accurate source of spatial information within the data system that makes up the finished map. Additional layers of data such as labels, symbols and paths are then added to the basemap to create the final product.  

Feature

Any real-world object that is represented on a map is a feature. Features can encompass large areas of a map, such as bodies of water and mountain ranges, or they can be discreet objects like parking areas, public washrooms or fire hydrants.

Attribute

Attribute data is information about spatial features and is stored in tables. It is also the information that specifies the appearance and labeling of features on a map. For example, the graphic attributes of a river might include the thickness of the line, line length, color, and the name used for labeling.

Control Point

A control point is a location on the map with known pixel (x,y) coordinates. Control points are used in georeferencing to allow for extrapolation of the relative location of other points whose exact coordinates may not be known.

Coordinate System

A coordinate system is a reference system used to represent the locations of geographic features on a map. It provides the basis for identifying locations on the earth’s surface. There are thousands of different coordinate systems, most of which are limited in use to highly specialized purposes.

Projection

The earth is not flat and so imagining that it is for the purpose of putting it on a 2-dimensional map results in some distortion. A projection is a method by which the curved surface of the earth is portrayed on a flat surface and is based on a mathematical transformation of the earth’s lines of longitude and latitude onto a plane. There are many different projections, each of which distorts distance, area, shape, and direction is some way, therefore no projection can result in a perfectly accurate flat map. Check out the Avenza Projections Guide for a more detailed information.

Georeferencing

Georeferencing involves aligning geographic data to a known coordinate system so it can be viewed, queried, and analyzed relative to other geographic data on the same map. Georeferencing may involve shifting, rotating, scaling, skewing, and in some cases warping, rubber sheeting, or orthorectifying the data to improve accuracy.

Graticules and grids

Graticules are the network of longitude and latitude lines on a map or chart that relates points on a map to their true locations on the earth. You can think of this a grid system – in fact, the terms are sometimes used interchangeably, but there is a subtle difference. Graticules are derived from 3-dimensional ellipsoidal shape of the earth and are formed by the the lines of latitude (parallel lines circling the earth), and lines of longitude (non-parallel lines converging at the earth’s poles). A grid system is comprised of a set of parallel and perpendicular lines that are superimposed on a flat projection of the earth, creating an x,y coordinate system. An example of a grid system is the Universal Transverse Mercator (UTM) system.

Themes

In MAPublisher, MAP Themes are a collection of thematic cartography tools designed to automate how styles and symbols are applied, charts are produced, and data is plotted. There are three themes which you can be customized to suit your needs: Stylesheet, Chart, and Dot Density. MAP Themes offer a lot of flexibility as they can be edited, applied, duplicated, automated, exported, and cleared without affecting the spatial referencing of map features.

This is just a small sampling of the more robust glossary of terms available in the our MAPublisher and Geographic Imager documentation packages.

Sources
http://www.avenza.com/help/mapublisher/10.1/index.html?whats_new_in_mapublisher.htm
http://www.avenza.com/help/geographic-imager/5.3/index.html?glossary.htm
https://www.gislounge.com/gis-dictionary/
http://geography.name/gridgraticule/