uff.point

Parameter	Type	Description
distance	double	distance from the point location to the origin of coordinates [m]
azimuth	double	angle from the point location to the plane YZ [rad]
elevation	double	angle from the point location to the plane XZ [rad]

The uff.point class defines a point in a three-dimensional space in spherical coordinates. Contrary to cartersian coordinates, spherical coordinates enable us to define a point at an infinite distance but in a given direction. This feature is exploited to define plane-waves as produced by a point source at infinity.

To make the class more accesible dependent parameters are defined. The location of the point in Cartersian coordinates can be accessed as parameters 'x','y','z', and 'xyz'. For instance by

#!matlab


> my_point=uff.point('distance',20e-3,'azimuth',0.5);
>> my_point.xyz
ans =
    0.0096         0    0.0176

But these dependent variables can also be set. For instance by

#!matlab

my_point=uff.point('xyz',[-10e-3 0 20e-3]);
my_point.azimuth
ans =
   -0.4636

This allows to set point locations also in Cartesian coordinates. The conversion code is available below. Some other methods allow to plot the point in a Figure.

#!matlab

         function h=set.x(h,in_x)
             assert(numel(in_x)==1, 'The x must be an scalar in [m]');
              % update spherical
              y=h.y;
              z=h.z;
              h.distance=norm([in_x y z],2);
              h.azimuth=atan2(in_x,z);
              if(h.distance>0)
                h.elevation=asin(y/h.distance);
              else
                h.elevation=0;
              end
         end
         function h=set.y(h,in_y)
             assert(numel(in_y)==1, 'The y must be an scalar in [m]');
              x=h.x;
              z=h.z;
              h.distance=norm([x in_y z],2);
              if(h.distance>0)
                h.elevation=asin(in_y/h.distance);
              else
                h.elevation=0;
              end
         end
         function h=set.z(h,in_z)
             assert(numel(in_z)==1, 'The z must be an scalar in [m]');
              x=h.x;
              y=h.y;
              h.distance=norm([x y in_z],2);
              h.azimuth=atan2(x,in_z);
              if(h.distance>0)
                h.elevation=asin(y/h.distance);
              else
                h.elevation=0;
              end
         end

File Example

An example of a HDF5 file containing a uff.point data strcuture can be downloaded from here. Use any HDF5 viewer to inspect it, such as HDFView

Wiki

UFF / other_formats / USTB point

uff.point

File Example