daspectm
Control vertical exaggeration in map display
Syntax
daspectm(zunits)
daspectm(zunits,vfac)
daspectm(zunits,vfac,lat,long)
daspectm(zunits,vfac,lat,long,az)
daspectm(zunits,vfac,lat,long,az,radius)
Description
daspectm(zunits) sets the
'DataAspectRatio' property of the map axes so that the
z-axis is in proportion to the x-and
y-projected coordinates. This permits elevation data to be
displayed without vertical distortion. The zunits parameter specifies
the units of the elevation data, and can be any length units recognized by
unitsratio.
daspectm(zunits,vfac) sets the
'DataAspectRatio' property so that the
z-axis is vertically exaggerated by the factor
vfac. If omitted, the default is no vertical exaggeration.
daspectm(zunits,vfac,lat,long) sets the aspect ratio
based on the local map scale at the specified geographic location. If omitted, the
default is the center of the map limits.
daspectm(zunits,vfac,lat,long,az) also specifies the
direction along which the scale is computed. If omitted, 90 degrees (west) is
assumed.
daspectm(zunits,vfac,lat,long,az,radius) specifies the
radius of the sphere. radius can be one of the values supported by
km2deg, or it can be the (numerical)
radius of the desired sphere in zunits. If omitted, the default
radius of the Earth is used.
Examples
Display Elevation Map with Vertical Exaggeration
Load elevation data and a geographic cells reference object for the Korean peninsula. Create a world map with appropriate latitude and longitude limits, then display the data using meshm. Apply a colormap appropriate for elevation data using demcmap. Then, view the map in 3-D.
load korea5c
latlim = korea5cR.LatitudeLimits;
lonlim = korea5cR.LongitudeLimits;
worldmap(latlim,lonlim)
meshm(korea5c,korea5cR,korea5cR.RasterSize,korea5c)
demcmap(korea5c)
view(3)
Set the vertical exaggeration factor to 30 using daspectm. Add light using camlight.
daspectm('m',30)
camlight
Limitations
The relationship between the vertical and horizontal coordinates
holds only as long as the geoid or scale factor
properties of the map axes remain unchanged. If you change the scaling
between geographic coordinates and projected axes coordinates, execute daspectm again.