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diff --git a/tde-i18n-en_GB/docs/tdeedu/kstars/geocoords.docbook b/tde-i18n-en_GB/docs/tdeedu/kstars/geocoords.docbook index 5f8d87bf8a7..96330b24325 100644 --- a/tde-i18n-en_GB/docs/tdeedu/kstars/geocoords.docbook +++ b/tde-i18n-en_GB/docs/tdeedu/kstars/geocoords.docbook @@ -1,66 +1,15 @@ <sect1 id="ai-geocoords"> <sect1info> -<author -><firstname ->Jason</firstname -> <surname ->Harris</surname -> </author> +<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 centre 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 centre 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> +<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 centre 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 centre 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> +<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> |