Mapping Toolbox

Displaying Matrix Maps

The Mapping Toolbox provides functions for the display and enhancement of both regular and general matrix maps in a variety of formats. Recall that regular matrix maps require a map legend vector that describes the scale and location of the map, while general matrix maps require matrices of latitude and longitude coordinates.

The matrix map display functions are geographic analogies to the MATLAB surface drawing commands. Like the line plotting functions discussed in the previous chapter, the Mapping Toolbox function names are usually identical to their MATLAB counterparts, except for the addition of an 'm.' For instance, the Mapping Toolbox functions, surfacem and surfm, are analogous to MATLAB's surface and surf commands. You will most likely find a Mapping Toolbox version of a MATLAB surface drawing function by appending an 'm' to the MATLAB function name.

Note    In the Mapping Toolbox, the set of functions beginning with 'mesh' are used for regular matrix maps, while those with 'surf' are reserved for general matrix maps. It should be noted here that this usage differs entirely from MATLAB's definition; that is, mesh plots are used for colored, wire-frame views of the surface, while surf displays colored, faceted surfaces.

Surface map objects can be displayed in a variety of different ways. You can assign colors from the figure colormap to surfaces according to the value of their data. You can also display images where the matrix data consists of indices into a colormap or display the matrix as a three-dimensional surface, with the z coordinates given by the map matrix. You can use monochrome surfaces that reflect a "pseudo-light" source, thereby producing a three-dimensional, shaded relief model of the surface. Finally, you can use a combination of color and light shading to create a lighted shaded relief map.

The following table lists the available Mapping Toolbox surface map display functions:

Function	Used to Create
meshm	Regular matrix map warped to projected graticule mesh
surfm	General matrix map projected on map axes
imagem	Regular matrix map displayed as image
pcolorm	Projected matrix map in z = 0 plane
surfacem	Matrix map warped to projected graticule mesh
surflm	3-D shaded surface with lighting projected on map axes
meshlsrm	3-D lighted shaded relief of regular matrix map
surflsrm	3-D lighted shaded relief of general matrix map

Displaying Vector Maps as Patches

The Graticule