Introduction to Mapping Graphics

Even though geospatial data often is manipulated and analyzed without being displayed, high-quality interactive cartographic displays can play valuable roles in exploratory data analysis, application development, and presentation of results.

Using Mapping Toolbox capabilties, you can display geographic information almost as easily as you can display tabular or time-series data in MATLAB plots. Most mapping functions are similar to MATLAB plotting functions, except they accept data with geographic/geodetic coordinates (latitudes and longitudes) instead of Cartesian and polar coordinates. Mapping functions typically have the same names as their MATLAB counterparts, with the addition of an 'm' suffix (for maps). For example, the Mapping Toolbox analog to the MATLAB plot function is plotm.

Mapping Toolbox software manages most of the details in displaying a map. It projects your data, cuts and trims it to specified limits, and displays the resulting map at various scales. With the toolbox you can also add customary cartographic elements, such as a frame, grid lines, coordinate labels, and text labels, to your displayed map. If you change your projection properties, or even the projection itself, some Mapping Toolbox map displays are automatically redrawn with the new settings, undoing any cuts or trims if necessary. See Accessing, Computing, and Inverting Map Projection Data for information on how to project data without displaying it.

The toolbox also makes it easy to modify and manipulate maps. You can modify the map display and mapped objects either from the command line or through and property editing tools you can invoke by clicking on the display.

Note   In its current implementation, the toolbox maintains the map projection and display properties by storing special data in the UserData property of the map axes. The toolbox also takes over the UserData property of mapped objects. Therefore, never attempt to set the UserData property of a map axes or a projected map object. Do not apply the MATLAB get function to axes UserData, depend on the contents of UserData in any way, or apply functions that set or get UserData to the handles of map axes or mapped objects. Only use the Mapping Toolbox functions getm and setm to obtain and modify map axes properties.

Creating and Viewing Maps

Using worldmap and usamap

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