Postgisni ma'lumotlar bazasiga ulaymiz.

CREATE EXTENSION postgis;

Agar postgisni oldin o'rnatmagan bo'lsangiz quyidagi buyruqni terminalga yozib postgisni o'rnating.

sudo apt-get install postgresql-12-postgis-3

12 yoki 3 vaqt o'tishi bilan yangi talqinlarga o'zgarishi mumkin.

Jadval yaratmiz

CREATE TABLE oraliqmasofa (
    id serial NOT NULL,
    joy_nomi varchar(255) NOT NULL,
    location Point NOT NULL,
    PRIMARY KEY (id)
);

Jadvalga joy nomi va kordinatalarni kiritamiz.
(X gorizontal 41.2701661 va Y vertikal 69.3053935)

INSERT INTO oraliqmasofa (joy_nomi, location) VALUES 
( 'Toshkent', '(41.2701661, 69.3053935)' ),
( 'Andijon', '(40.7794781, 72.3737798)' );


SELECT * FROM oraliqmasofa;

id | joy_nomi | location
----+-----------+-------------------
1 | Toshkent | (41.2701661, 69.3053935)
2 | Andijon | (40.7794781, 72.3737798)
(2 rows)


Endi masofani tanlash uchun biz har doim yerni mukammal shar sifatida ishlatadigan ST_Distance_Spheredan foydalanishimiz mumkin, bu juda tez, ammo ST_DistanceSpheroiddan kamroq aniqroq. Ikkalasini ham sinab ko'raman:

ST_Distance_Sphere

SELECT ST_Distance_Sphere(geometry(a.location), geometry(b.location))
FROM oraliqmasofa a, oraliqmasofa b
WHERE a.id=1 AND b.id=2;

Natija: 262,797.01645757 metr.

ST_Distance_Spheroid

SELECT ST_Distance_Spheroid(geometry(a.location), geometry(b.location), 'SPHEROID["WGS 84",6378137,298.257223563]')
FROM oraliqmasofa a, oraliqmasofa b
WHERE a.id=1 AND b.id=2;

Natija: 263,430.941199621 metr.

#location #postgres #masofa #maps #distance

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CHAR(n), VARCHAR(n), VARCHAR, text?

Eng maqbul yechim text ekan.

#postgres #text

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