Extensions
seg

seg

seg : data type for representing line segments or floating-point intervals

Overview

IDExtensionPackageVersionCategoryLicenseLanguage
3940
seg
seg
1.4
TYPE
PostgreSQL
C
AttributeHas BinaryHas LibraryNeed LoadHas DDLRelocatableTrusted
--s-dt-
No
Yes
No
Yes
no
yes
Relationships
See Also
cube
intarray
intagg
prefix
semver
unit
pgpdf
pglite_fusion

Packages

PG18PG17PG16PG15PG14
1.4
1.4
1.4
1.4
1.4

This is a built-in contrib extension ship with the PostgreSQL kernel

Install

Create this extension with:

CREATE EXTENSION seg;

Usage

seg: line segment / floating-point interval data type

The seg extension provides a data type for representing line segments or floating-point intervals, useful for representing measurements with uncertainty.

CREATE EXTENSION seg;

Input Formats 

SELECT '5.0'::seg;           -- zero-length interval (point)
SELECT '5.0 .. 7.0'::seg;    -- interval from 5.0 to 7.0
SELECT '5(+-)0.3'::seg;      -- interval 4.7 .. 5.3
SELECT '50 ..'::seg;          -- open interval >= 50
SELECT '.. 0'::seg;           -- open interval <= 0

Certainty indicators (<, >, ~) can be prepended but are treated as comments and ignored by operators.

Operators

Spatial operators (GiST-indexed):

OperatorDescription
<<Entirely left of
>>Entirely right of
&<Does not extend right of
&>Does not extend left of
=Equal
&&Overlaps
@>Contains
<@Contained in

Comparison operators (<, <=, >, >=) are available for sorting.

Index Support 

CREATE INDEX idx ON measurements USING gist (reading);

Precision

Values are stored as 32-bit floating-point pairs, retaining up to 7 significant digits. Trailing zeroes are preserved.

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