[postgis-tickets] [SCM] PostGIS branch master updated. 3.2.0alpha1-46-g21c3f23
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commit 21c3f2351e2f8ab0ca3a95ad6fbba04378f4aece
Author: Martin Davis <mtnclimb at gmail.com>
Date: Thu Sep 30 15:03:20 2021 -0700
Add doc warning for maxdecdigits and invalid output
diff --git a/doc/reference_output.xml b/doc/reference_output.xml
index 94af796..f58c3d3 100644
--- a/doc/reference_output.xml
+++ b/doc/reference_output.xml
@@ -44,18 +44,29 @@
<refsection>
<title>Description</title>
- <para>Returns the Well-Known Text representation of the geometry prefixed with the SRID. Optional argument may be used to reduce the maximum number
+ <para>Returns the Well-Known Text representation of the geometry prefixed with the SRID.
+ The optional <parameter>maxdecimaldigits</parameter> argument may be used to reduce the maximum number
of decimal digits after floating point used in output (defaults to 15).</para>
+ <para>To perform the inverse conversion of EWKT representation to PostGIS geometry
+ use <xref linkend="ST_GeomFromEWKT" />.</para>
+
+ <warning>
+ <para>Using the <parameter>maxdecimaldigits</parameter> parameter
+ can cause output geometry to become invalid.
+ To avoid this use <xref linkend="ST_ReducePrecision" />
+ with a suitable gridsize first.
+ </para>
+ </warning>
+
<note>
- <para>The WKT spec does not include the SRID. To get the OGC WKT format use ST_AsText.</para>
+ <para>The WKT spec does not include the SRID. To get the OGC WKT format use <xref linkend="ST_AsText" />.</para>
</note>
<warning>
- <para>WKT format does not maintain precision so to prevent floating truncation, use ST_AsBinary or ST_AsEWKB format for transport.</para>
+ <para>WKT format does not maintain precision so to prevent floating truncation,
+ use <xref linkend="ST_AsBinary" /> or <xref linkend="ST_AsEWKB" /> format for transport.</para>
</warning>
- <note>
- <para>ST_AsEWKT is the reverse of <xref linkend="ST_GeomFromEWKT" />. Use <xref linkend="ST_GeomFromEWKT" /> to convert to a postgis geometry from ST_AsEWKT representation.</para>
- </note>
+
<para>Enhanced: 3.1.0 support for optional precision parameter.</para>
<para>Enhanced: 2.0.0 support for Geography, Polyhedral surfaces, Triangles and TIN was introduced.</para>
@@ -147,7 +158,15 @@ CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)
<para>The textual representation of numbers in WKT may not maintain full floating-point precision.
To ensure full accuracy for data storage or transport it is best to use
<link linkend="OpenGISWKBWKT">Well-Known Binary</link> (WKB) format
- (see <xref linkend="ST_AsBinary" /> and <xref linkend="ST_AsEWKB" />).</para>
+ (see <xref linkend="ST_AsBinary" /> and <parameter>maxdecimaldigits</parameter>).</para>
+ </warning>
+
+ <warning>
+ <para>Using the <parameter>maxdecimaldigits</parameter> parameter
+ can cause output geometry to become invalid.
+ To avoid this use <xref linkend="ST_ReducePrecision" />
+ with a suitable gridsize first.
+ </para>
</warning>
<para>Availability: 1.5 - support for geography was introduced.</para>
@@ -629,6 +648,14 @@ F000000000000000000000000000000000000000000000000');
<para>The <varname>maxdecimaldigits</varname> argument may be used to reduce the maximum number of decimal places used in output (defaults to 9). If you are using EPSG:4326 and are outputting the geometry only for display, <varname>maxdecimaldigits</varname>=6 can be a good choice for many maps.</para>
+ <warning>
+ <para>Using the <parameter>maxdecimaldigits</parameter> parameter
+ can cause output geometry to become invalid.
+ To avoid this use <xref linkend="ST_ReducePrecision" />
+ with a suitable gridsize first.
+ </para>
+ </warning>
+
<para>The <varname>options</varname> argument can be used to add BBOX or CRS in GeoJSON output:
<itemizedlist>
<listitem>
@@ -791,6 +818,15 @@ FROM (VALUES (1, 'one', 'POINT(1 1)'::geometry)) AS t(id, name, geom);</programl
specified then the default is assumed to be 2. The <varname>maxdecimaldigits</varname> argument
may be used to reduce the maximum number of decimal places
used in output (defaults to 15).</para>
+
+ <warning>
+ <para>Using the <parameter>maxdecimaldigits</parameter> parameter
+ can cause output geometry to become invalid.
+ To avoid this use <xref linkend="ST_ReducePrecision" />
+ with a suitable gridsize first.
+ </para>
+ </warning>
+
<para>GML 2 refer to 2.1.2 version, GML 3 to 3.1.1 version</para>
<para>The 'options' argument is a bitfield. It could be used to define CRS output type
in GML output, and to declare data as lat/lon:
@@ -973,6 +1009,14 @@ SELECT ST_AsGML(3, ST_GeomFromEWKT('POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0
maximum number of decimal places used in
output (defaults to 15), version default to 2 and default namespace is no prefix.</para>
+ <warning>
+ <para>Using the <parameter>maxdecimaldigits</parameter> parameter
+ can cause output geometry to become invalid.
+ To avoid this use <xref linkend="ST_ReducePrecision" />
+ with a suitable gridsize first.
+ </para>
+ </warning>
+
<para>Version 1: ST_AsKML(geom_or_geog, maxdecimaldigits) / version=2 / maxdecimaldigits=15 </para>
<para>Version 2: ST_AsKML(version, geom_or_geog, maxdecimaldigits, nprefix) maxdecimaldigits=15 / nprefix=NULL </para>
-----------------------------------------------------------------------
Summary of changes:
doc/reference_output.xml | 58 ++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 51 insertions(+), 7 deletions(-)
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