Copy the KDE 3.5 branch to branches/trinity for new KDE 3.5 features.

BUG:215923


git-svn-id: svn://anonsvn.kde.org/home/kde/branches/trinity/kdeedu@1054174 283d02a7-25f6-0310-bc7c-ecb5cbfe19da

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+<sect1 id="ai-geocoords">
+<sect1info>
+<author>
+<firstname>Jason</firstname>
+<surname>Harris</surname>
+</author>
+</sect1info>
+<title>Geographic Coordinates</title>
+<indexterm><primary>Geographic Coordinate System</primary></indexterm>
+<indexterm><primary>Longitude</primary><see>Geographic Coordinate System</see></indexterm>
+<indexterm><primary>Latitude</primary><see>Geographic Coordinate System</see></indexterm>
+<para>
+Locations on Earth can be specified using a spherical coordinate system.
+The geographic (<quote>earth-mapping</quote>) coordinate system is aligned
+with the spin axis of the Earth.  It defines two angles measured from
+the center of the Earth.  One angle, called the <firstterm>Latitude</firstterm>,
+measures the angle between any point and the Equator.  The other angle, called
+the <firstterm>Longitude</firstterm>, measures the angle
+<emphasis>along</emphasis> the Equator from an arbitrary point on the Earth
+(Greenwich, England is the accepted zero-longitude point in most modern
+societies).
+</para><para>
+By combining these two angles, any location on Earth can be specified.
+For example, Baltimore, Maryland (USA) has a latitude of 39.3 degrees
+North, and a longitude of 76.6 degrees West.  So, a vector drawn from
+the center of the Earth to a point 39.3 degrees above the Equator and
+76.6 degrees west of Greenwich, England will pass through Baltimore.
+</para><para>
+The Equator is obviously an important part of this coordinate system; it
+represents the <emphasis>zeropoint</emphasis> of the latitude angle, and the
+halfway point between the poles.  The Equator is the <firstterm>Fundamental
+Plane</firstterm> of the geographic coordinate system.  <link
+linkend="ai-skycoords">All Spherical Coordinate Systems</link> define such a
+Fundamental Plane.
+</para><para>
+Lines of constant Latitude are called <firstterm>Parallels</firstterm>.  They
+trace circles on the surface of the Earth, but the only parallel that is a <link
+linkend="ai-greatcircle">Great Circle</link> is the Equator (Latitude=0
+degrees).    Lines of constant Longitude are called
+<firstterm>Meridians</firstterm>.  The Meridian passing through Greenwich is the
+<firstterm>Prime Meridian</firstterm> (longitude=0 degrees).  Unlike Parallels,
+all Meridians are great circles, and Meridians are not parallel: they intersect
+at the north and south poles.
+</para>
+<tip>
+<para>Exercise:</para>
+<para>
+What is the longitude of the North Pole?  Its latitude
+is 90 degrees North.
+</para>
+<para>
+This is a trick question.  The Longitude is meaningless at the north pole (and the
+south pole too).  It has all longitudes at the same time.
+</para>
+</tip>
+</sect1>