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 string zunits 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) uses the last input to determine the radius of the sphere. radius can be one of the strings 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

expand all

Elevation Map with Vertical Exaggeration

Show the elevation map of the Korean peninsula with a vertical exaggeration factor of 30.

Read data from the MAT-file containing information about the Korean peninsula.

load korea

Display the data grid.

[latlim,lonlim] = limitm(map,refvec);
worldmap(latlim,lonlim)
meshm(map,refvec,size(map),map)
demcmap(map)
view(3)

Set the vertical exaggeration factor.

daspectm('m',30)
tightmap
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.

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