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<html>
<head>
<title>
SPHERE_XYZF_DISPLAY - Display Unit Sphere + 3D Points + Faces in the 3D MATLAB Graphics Window
</title>
</head>
<body bgcolor="#EEEEEE" link="#CC0000" alink="#FF3300" vlink="#000055">
<h1 align = "center">
SPHERE_XYZF_DISPLAY <br>
Display Unit Sphere + 3D Points + Faces <br>
in the 3D MATLAB Graphics Window
</h1>
<hr>
<p>
<b>SPHERE_XYZF_DISPLAY</b>
is a MATLAB program which
reads information identifying
an XYZ data file containing a list of 3D point coordinates
and an XYZF file listing point indices that form faces,
and displays a unit sphere, the points, and the faces,
in a 3D MATLAB graphics window.
</p>
<p>
It is difficult to visualize points and faces that lie on the unit
sphere. You can't see the curving surface, and you can see points
and faces that should not be visible, because they are on the other side of
the sphere. By starting the display with a unit sphere, and then
adding the 3D points and faces you want to see, both of these problems are
resolved. The addition of the sphere gives important visual cues
as to how to "read" the data.
</p>
<p>
The files containing the point coordinates and the face indices are
in the <b>XYZ</b> and <b>XYZF</b> formats respectively.
The MATLAB command <b>patch</b> is used to display the faces, and
<b>plot3</b> displays the points. The sphere is generated by the
<b>sphere</b> command and displayed with the <b>surf</b> command.
</p>
<p>
<b>SPHERE_XYZF_DISPLAY</b> is essentially a version of <b>XYZF_DISPLAY</b>
with the addition of a displayed sphere. It seems like a small change,
but for spherical point data, it makes a huge difference.
</p>
<h3 align = "center">
Usage:
</h3>
<p>
<blockquote>
<b>sphere_xyzf_display</b> ( <i>'prefix'</i> )
</blockquote>
where
<ul>
<li>
<i>'prefix'</i>.xyz is an XYZ file of point coordinates;
</li>
<li>
<i>'prefix'</i>.xyzf is an XYZF file of point indices forming faces;
</li>
</ul>
and displays a plot of the points and faces.
</p>
<h3 align = "center">
Licensing:
</h3>
<p>
The computer code and data files described and made available on this web page
are distributed under
<a href = "../../txt/gnu_lgpl.txt">the GNU LGPL license.</a>
</p>
<h3 align = "center">
Languages:
</h3>
<p>
<b>SPHERE_XYZF_DISPLAY</b> is available in
<a href = "../../m_src/sphere_xyzf_display/sphere_xyzf_display.html">a MATLAB version</a>.
</p>
<h3 align = "center">
Related Data and Programs:
</h3>
<p>
<a href = "../../m_src/ball_and_stick_display/ball_and_stick_display.html">
BALL_AND_STICK_DISPLAY</a>,
a MATLAB program which
demonstrates the creation of a 3D ball and stick image;
</p>
<p>
<a href = "../../m_src/mpas_grid_display/mpas_grid_display.html">
MPAS_GRID_DISPLAY</a>,
a directory of MATLAB programs which
can read an MPAS NETCDF grid file and display the primary polygonal
mesh or the dual triangular mesh.
</p>
<p>
<a href = "../../m_src/ply_display/ply_display.html">
PLY_DISPLAY</a>,
a MATLAB program which
displays an image of a 3D graphics file in PLY format;
</p>
<p>
<a href = "../../m_src/quad_surface_display/quad_surface_display.html">
QUAD_SURFACE_DISPLAY</a>
a MATLAB program which
reads files defining a 3D quadrilateral mesh surface and displays it
within MATLAB.
</p>
<p>
<a href = "../../m_src/sphere_cvt/sphere_cvt.html">
SPHERE_CVT</a>
is a MATLAB library which
creates a mesh of well-separated points on a unit sphere by applying the
Centroidal Voronoi Tessellation (CVT) iteration.
</p>
<p>
<a href = "../../m_src/sphere_delaunay/sphere_delaunay.html">
SPHERE_DELAUNAY</a>,
a MATLAB program which
computes the Delaunay triangulation of points on a sphere.
</p>
<p>
<a href = "../../f_src/sphere_design_rule/sphere_design_rule.html">
SPHERE_DESIGN_RULE</a>
is a FORTRAN90 library which
returns point sets on the surface of the unit sphere, known as "designs",
which can be useful for estimating integrals on the surface, among other uses.
</p>
<p>
<a href = "../../datasets/sphere_grid/sphere_grid.html">
SPHERE_GRID</a>,
a dataset directory which
contains grids of points, lines, triangles or quadrilaterals on a sphere;
</p>
<p>
<a href = "../../m_src/sphere_grid/sphere_grid.html">
SPHERE_GRID</a>,
a MATLAB library which
provides a number of ways of generating grids of points, or of
points and lines, or of points and lines and faces, over the unit sphere.
</p>
<p>
<a href = "../../m_src/sphere_voronoi/sphere_voronoi.html">
SPHERE_VORONOI</a>,
a MATLAB program which
computes the Voronoi diagram of points on a sphere.
</p>
<p>
<a href = "../../cpp_src/sphere_voronoi_display_opengl/sphere_voronoi_display_opengl.html">
SPHERE_VORONOI_DISPLAY_OPENGL</a>,
a C++ program which
displays a sphere and randomly selected generator points, and then
gradually colors in points in the sphere that are closest to each generator.
</p>
<p>
<a href = "../../m_src/sphere_xyz_display/sphere_xyz_display.html">
SPHERE_XYZ_DISPLAY</a>
is a MATLAB program which
reads XYZ information defining points in 3D,
and displays a unit sphere and the points in the MATLAB graphics window.
</p>
<p>
<a href = "../../cpp_src/sphere_xyz_display_opengl/sphere_xyz_display_opengl.html">
SPHERE_XYZ_DISPLAY_OPENGL</a>
a C++ program which
reads XYZ information defining points in 3D,
and displays a unit sphere and the points, using OpenGL.
</p>
<p>
<a href = "../../m_src/tri_surface_display/tri_surface_display.html">
TRI_SURFACE_DISPLAY</a>
is a MATLAB program which
reads data defining a triangular mesh of a 3D surface and displays it.
</p>
<p>
<a href = "../../m_src/xyzf_display/xyzf_display.html">
XYZF_DISPLAY</a>
is a MATLAB program which
reads XYZF information defining points and faces in 3D,
and displays an image using OpenGL.
</p>
<p>
<a href = "../../cpp_src/xyzf_display_opengl/xyzf_display_opengl.html">
XYZF_DISPLAY_OPENGL</a>
a C++ program which
reads XYZF information defining points and faces in 3D,
and displays an image using OpenGL.
</p>
<h3 align = "center">
Source Code:
</h3>
<p>
<ul>
<li>
<a href = "sphere_xyzf_display.m">sphere_xyzf_display.m</a>
the source code.
</li>
</ul>
</p>
<h3 align = "center">
Examples and Tests:
</h3>
<p>
<b>FRED</b> is a pair of files containing the coordinates of 252 points
and the triples of indices that form 500 triangular faces.
<ul>
<li>
<a href = "fred.xyz">fred.xyz</a>, the point coordinates.
</li>
<li>
<a href = "fred.xyzf">fred.xyzf</a>, the face information;
</li>
<li>
<a href = "fred.png">fred.png</a>, a snapshot of the 3D plot.
</li>
</ul>
</p>
<p>
You can go up one level to <a href = "../m_src.html">
the MATLAB source codes</a>.
</p>
<hr>
<i>
Last revised on 31 August 2010.
</i>
<!-- John Burkardt -->
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