From: Regina Obe <lr@pcorp.us>
Date: Wed, 30 Dec 2009 15:12:49 +0000 (+0000)
Subject: Fix ST_Extent/ST_Expand docs to reflect change in behavior of outputting double preci... 
X-Git-Tag: 1.5.0b1~26
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=2292b762dbaf36ed452f41aee5f04a51c6c32da1;p=postgis

Fix ST_Extent/ST_Expand docs to reflect change in behavior of outputting double precision coords instead of float4.  Still need to fix up examples.

git-svn-id: http://svn.osgeo.org/postgis/trunk@5081 b70326c6-7e19-0410-871a-916f4a2858ee
---

diff --git a/doc/reference_accessor.xml b/doc/reference_accessor.xml
index 70aa4d9d7..ede5458d5 100644
--- a/doc/reference_accessor.xml
+++ b/doc/reference_accessor.xml
@@ -297,7 +297,7 @@ SELECT ST_AsEWKT(ST_EndPoint('LINESTRING(1 1 2, 1 2 3, 0 0 5)'));
 		  <refnamediv>
 			<refname>ST_Envelope</refname>
 
-			<refpurpose>Returns a geometry representing the bounding box of the
+			<refpurpose>Returns a geometry representing the double precision (float8) bounding box of the
 			supplied geometry.</refpurpose>
 		  </refnamediv>
 
@@ -314,7 +314,7 @@ SELECT ST_AsEWKT(ST_EndPoint('LINESTRING(1 1 2, 1 2 3, 0 0 5)'));
 		  <refsection>
 			<title>Description</title>
 
-			<para>Returns the float4 minimum bounding box for the supplied geometry, as a geometry.
+			<para>Returns the float8 minimum bounding box for the supplied geometry, as a geometry.
 			The polygon is defined by the corner points of the bounding box
 			((<varname>MINX</varname>, <varname>MINY</varname>),
 			(<varname>MINX</varname>, <varname>MAXY</varname>),
@@ -328,17 +328,7 @@ SELECT ST_AsEWKT(ST_EndPoint('LINESTRING(1 1 2, 1 2 3, 0 0 5)'));
 			lower dimension than <varname>POLYGON</varname>, ie.
 			<varname>POINT</varname> or <varname>LINESTRING</varname>.</para>
 
-			<caution>
-			  <para>In PostGIS, the bounding box of a geometry is represented internally using
-			  <varname>float4</varname>s instead of <varname>float8</varname>s that are used
-			  to store geometries.  The bounding box coordinates are floored, guarenteeing
-			  that the geometry is contained entirely within its bounds.  This has the
-			  advantage that a geometry's bounding box is half the size as the minimum
-			  bounding rectangle, which means significantly faster indexes and general performance.
-			  But it also means that the bounding box is NOT the same as the minimum bounding
-			  rectangle that bounds the geometry.</para>
-			</caution>
-
+			<para>Availability: 1.5.0 behavior changed to output double precision instead of float4</para>
 			<para>&sfs_compliant; s2.1.1.1</para>
 			<para>&sqlmm_compliant; SQL-MM 3: 5.1.15</para>
 		</refsection>
@@ -375,17 +365,7 @@ SELECT ST_AsText(ST_Envelope('POLYGON((0 0, 0 1, 1.0000000001 1, 1.0000000001 0,
 SELECT Box3D(geom), Box2D(geom), ST_AsText(ST_Envelope(geom)) As envelopewkt
 	FROM (SELECT 'POLYGON((0 0, 0 1000012333334.34545678, 1.0000001 1, 1.0000001 0, 0 0))'::geometry As geom) As foo;
 
-box3d
------------------------------------------
-BOX3D(0 0 0,1.0000001 1000012333334.35 0)
-
-box2d
-------------------------------------------
-BOX(0 0,1.00000011920929 1000012382208)
-
-envelopewkt
--------------------------------------------------------------------
-POLYGON((0 0,0 1000012382208,1.00000011920929 1000012382208,1.00000011920929 0,0 0))
+<!-- TODO: Fix examples to reflect new behavior -->
 	</programlisting>
 	  </refsection>
 	  <refsection>
diff --git a/doc/reference_misc.xml b/doc/reference_misc.xml
index 1d8b063de..13b62bd70 100644
--- a/doc/reference_misc.xml
+++ b/doc/reference_misc.xml
@@ -221,7 +221,7 @@ BOX(-124.659652709961 24.6830825805664,-67.7798080444336 49.0012092590332)
 	<refentry id="ST_Expand">
 	  <refnamediv>
 		<refname>ST_Expand</refname>
-		<refpurpose>Returns bounding box expanded in all directions from the bounding box of the input geometry</refpurpose>
+		<refpurpose>Returns bounding box expanded in all directions from the bounding box of the input geometry. Uses double-precision</refpurpose>
 	  </refnamediv>
 
 	  <refsynopsisdiv>
@@ -251,7 +251,7 @@ BOX(-124.659652709961 24.6830825805664,-67.7798080444336 49.0012092590332)
 
 		<para>This function returns a bounding box expanded in all
 		directions from the bounding box of the input geometry, by an
-		amount specified in the second argument. Very useful for
+		amount specified in the second argument. Uses double-precision. Very useful for
 		distance() queries, or bounding box queries to add an index filter to the query.</para>
 		<para>There are 3 variants of this.  The one that takes a geometry will return a POLYGON geometry representation
 			of the bounding box and is the most commonly used variant.</para>
@@ -268,6 +268,10 @@ BOX(-124.659652709961 24.6830825805664,-67.7798080444336 49.0012092590332)
 		<note>
 		  <para>Bounding boxes of all geometries are currently 2-d even if they are 3-dimensional geometries.</para>
 		</note>
+		
+		<note>
+			<para>Availability: 1.5.0 behavior changed to output double precision instead of float4 coordinates.</para>
+		</note>
 
 	  </refsection>
 
@@ -275,6 +279,7 @@ BOX(-124.659652709961 24.6830825805664,-67.7798080444336 49.0012092590332)
 		<title>Examples</title>
 		<note><para>Examples below use US National Atlas Equal Area (SRID=2163) which is a meter projection</para></note>
 		<programlisting>
+		<!-- TODO: fix results of documentation to reflect new behavior -->
 --10 meter expanded box around bbox of a linestring
 SELECT CAST(ST_Expand(ST_GeomFromText('LINESTRING(2312980 110676,2312923 110701,2312892 110714)', 2163),10) As box2d);
 					 st_expand