The <function>area</function> function returns the area of a

spherical object in square radians. Supported data types are:

<type>scircle</type>, <type>spolygon</type> (if the polygon

is convex), and <type>sbox</type>.

is convex),<type>sbox</type>,and <type>smoc</type>.

</para>

<example>

<title>Area of a spherical circle as a multiple of &pgr;</title>

<![CDATA[ area]]>

<![CDATA[------]]>

<![CDATA[ 1]]>

<![CDATA[(1 row)]]>

<![CDATA[sql> SELECT area(smoc '0/1-3');]]>

<![CDATA[ area]]>

<![CDATA[-------------------]]>

<![CDATA[ 3.141592653589793]]>

<![CDATA[(1 row)]]>

</programlisting>

</example>

</programlisting>

</example>

<funcsynopsis>

<funcprototype>

<funcdef><function>smoc_area</function></funcdef>

<paramdef>smoc</paramdef>

</funcprototype>

</funcsynopsis>

<para>

Returns the size of an smoc in order 29 pixels.

</para>

<funcsynopsis>

<funcprototype>

<funcdef><function>smoc_degrade</function></funcdef>

</funcsynopsis>

<para>

<type>smoc</type> union and intersection are available as aggregate functions

that compute the aggretatedarea over a given column.

that compute the aggretatedcoverage over a given column.

</para>

<example>

<title>Computing the overall coverage of a catalog</title>

SET client_min_messages = 'notice';

--SETclient_min_messages ='warning';

SETextra_float_digits =0; -- make results compatible with 9.6 .. 11

SELECT smoc(''); -- expected: '0/'

smoc

------

version: 0, order: 0, depth: 1, first: 288230376151711744, last: 864691128455135232, area: 576460752303423488, tree_begin: 48, data_begin: 72

(1 row)

SELECT area('0/'::smoc);

area

------

0

(1 row)

SELECT area('29/1'::smoc);

area

----------------------

3.63319635209232e-18

(1 row)

SELECT area('0/1-3'::smoc);

area

------------------

3.14159265358979

(1 row)

SELECT area('0/0-11'::smoc);

area

------------------

12.5663706143592

(1 row)

SELECT '(0.78, 0.81)'::spoint <@ '7/123-456,10000-20000'::smoc;

?column?

----------

Smoc*moc= (Smoc*)PG_DETOAST_DATUM_SLICE(PG_GETARG_DATUM(0),0,

MOC_HEADER_VARSIZE);

PG_RETURN_INT64(moc->area);

PG_RETURN_FLOAT8(moc->area*4.0*M_PI /MOC_AREA_ALL_SKY);

}

IMMUTABLE

STRICT;

CREATE FUNCTIONsmoc_area (smoc)

RETURNSbigint

AS 'MODULE_PATHNAME'

CREATE FUNCTIONarea (smoc)

RETURNSdouble precision

AS 'MODULE_PATHNAME', 'smoc_area'

LANGUAGE C

PARALLEL SAFE

IMMUTABLE

SET client_min_messages='notice';

SELECT smoc('');-- expected: '0/'

SELECT'0/'::smoc;-- expected: '0/'

SELECT smoc_info('0/'::smoc);

SELECT smoc_info('0/1-2'::smoc);

SELECT area('0/'::smoc);

SELECT area('29/1'::smoc);

SELECT area('0/1-3'::smoc);

SELECT area('0/0-11'::smoc);

SELECT'(0.78, 0.81)'::spoint<@'7/123-456,10000-20000'::smoc;

SELECT'(0.78, 0.81)'::spoint<@'7/123-456,1000-2000'::smoc;