Categories:

地理空間関数, 変換関数

TRY_TO_GEOMETRY

Parses an input and returns a value of type GEOMETRY.

This function is essentially identical to TO_GEOMETRY except that it returns NULL when TO_GEOMETRY would issue an error.

See also:

TO_GEOMETRY

Syntax

Use one of the following:

TRY_TO_GEOMETRY( <varchar_expression> )

TRY_TO_GEOMETRY( <binary_expression> )

TRY_TO_GEOMETRY( <variant_expression> )

Arguments

varchar_expression

The argument must be a string expression that represents a valid geometric object in one of the following formats:

  • WKT (well-known text).

  • WKB (well-known binary) in hexadecimal format (without a leading 0x).

  • EWKT (extended well-known text).

  • EWKB (extended well-known binary) in hexadecimal format (without a leading 0x).

  • GeoJSON.

binary_expression

The argument must be a binary expression in WKB or EWKB format.

variant_expression

The argument must be an OBJECT in GeoJSON format.

Returns

The function returns a value of type GEOMETRY.

Usage Notes

  • Returns NULL if the input cannot be parsed as the appropriate supported format (WKT, WKB, EWKT, EWKB, GeoJSON).

  • For GeoJSON, WKT, and WKB input, the resulting GEOMETRY object has SRID set to 0. To change the SRID, pass the GEOMETRY object to ST_SETSRID, specifying the SRID that you want to set. ST_SETSRID returns the GEOMETRY object with that SRID set.

Examples

This shows a simple use of the TRY_TO_GEOMETRY function with VARCHAR data:

select try_to_geometry('INVALID INPUT');
+--------------------------------------+
| try_to_geometry('INVALID INPUT')     |
|--------------------------------------|
| NULL                                 |
+--------------------------------------+
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