meshlsrm
3-D lighted shaded relief of regular data grid
Syntax
meshlsrm(Z,R)
meshlsrm(Z,R,[azim elev])
meshlsrm(Z,R,[azim elev],cmap)
meshlsrm(Z,R,[azim elev],cmap,clim)
h = meshlsrm(...)
Description
meshlsrm(Z,R) displays the
regular data grid Z colored according to elevation
and surface slopes. R can be a referencing vector,
a referencing matrix, or a geographic raster reference object.
If R is a geographic raster reference object,
its RasterSize property must be consistent with size(Z).
If R is a referencing vector, it must be
a 1-by-3 with elements:
[cells/degree northern_latitude_limit western_longitude_limit]
If R is a referencing matrix, it must be
3-by-2 and transform raster row and column indices to/from geographic
coordinates according to:
[lon lat] = [row col 1] * R
If R is a referencing matrix, it must define
a (non-rotational, non-skewed) relationship in which each column of
the data grid falls along a meridian and each row falls along a parallel.
By default, shading is based on a light to the east (90 deg.) at an
elevation of 45 degrees. Also by default, the colormap is constructed
from 16 colors and 16 grays. Lighting is applied before the data
is projected. The current axes must have a valid map projection definition.
meshlsrm(Z,R,[azim elev]) displays
the regular data grid Z with the light coming from
the specified azimuth and elevation. Angles are specified in degrees,
with the azimuth measured clockwise from North, and elevation up from
the zero plane of the surface.
meshlsrm(Z,R,[azim elev],cmap) displays
the regular data grid Z using the specified colormap.
The number of grayscales is chosen to keep the size of the shaded
colormap below 256. If the vector of azimuth and elevation is
empty, the default locations are used. Color axis limits are computed
from the data.
meshlsrm(Z,R,[azim elev],cmap,clim) uses
the provided color axis limits, which by default are computed from
the data.
h = meshlsrm(...) returns
the handle to the surface drawn.
Examples
Load elevation data and a geographic cells reference object for the Korean peninsula. Create a
world map using appropriate latitude and longitude limits for the peninsula. Then,
display a lighted shaded relief map. By default, meshlsrm applies a
colormap appropriate for elevation data.
load korea5c worldmap(korea5c,korea5cR) meshlsrm(korea5c,korea5cR,[45 65])
Tips
This function effectively multiplies two colormaps, one with color based on elevation, the other with a grayscale based on the slope of the surface, to create a new colormap. This produces an effect similar to using a light on a surface, but with all of the visible colors actually in the colormap. Lighting calculations are performed on the unprojected data.