diff options
| -rw-r--r-- | doc/src/sgml/datatype.sgml | 20 |
1 files changed, 17 insertions, 3 deletions
diff --git a/doc/src/sgml/datatype.sgml b/doc/src/sgml/datatype.sgml index 2e637c36ebe..e6b975dfd0e 100644 --- a/doc/src/sgml/datatype.sgml +++ b/doc/src/sgml/datatype.sgml @@ -3264,7 +3264,7 @@ SELECT person.name, holidays.num_weeks FROM person, holidays </row> <row> <entry><type>line</type></entry> - <entry>32 bytes</entry> + <entry>24 bytes</entry> <entry>Infinite line</entry> <entry>{A,B,C}</entry> </row> @@ -3309,6 +3309,11 @@ SELECT person.name, holidays.num_weeks FROM person, holidays </table> <para> + In all these types, the individual coordinates are stored as + <type>double precision</type> (<type>float8</type>) numbers. + </para> + + <para> A rich set of functions and operators is available to perform various geometric operations such as scaling, translation, rotation, and determining intersections. They are explained in <xref linkend="functions-geometry"/>. @@ -3497,8 +3502,17 @@ SELECT person.name, holidays.num_weeks FROM person, holidays <para> Polygons are represented by lists of points (the vertexes of the - polygon). Polygons are very similar to closed paths, but are - stored differently and have their own set of support routines. + polygon). Polygons are very similar to closed paths; the essential + semantic difference is that a polygon is considered to include the + area within it, while a path is not. + </para> + + <para> + An important implementation difference between polygons and + paths is that the stored representation of a polygon includes its + smallest bounding box. This speeds up certain search operations, + although computing the bounding box adds overhead while constructing + new polygons. </para> <para> |