MySQL 8.0 GIS Overview

Copyright © 2018 Oracle and/or its afliates. All rights reserved.
MySQL 8.0 GIS Overview
Norvald H. Ryeng
Sofware Engineer
March 2018

3Copyright © 2018 Oracle and/or its afliates. All rights reserved.
Safe Harbor Statement
The following is intended to outline our general product directon. It is intended for
informaton purposes only, and may not be incorporated into any contract. It is not a
commitment to deliver any material, code, or functonality, and should not be relied upon
in making purchasing decisions. The development, release, and tming of any features or
functonality described for Oracle’s products remains at the sole discreton of Oracle.

Agenda
Data Types
Spatal Reference Systems
Functons
Indexes
Upgrade Issues
1
2
3
4
5
6
7

Data Types
● Geometry
– Point
– Linestring
– Polygon
– Geometry collecton
● Multpoint
● Multlinestring
● Multpolygon
Non-instantable, but can be used as column type.

SRID 0 Projected SRS
Cartesian SRS
5.7 8.0
Geographic SRS

● Each SRS has a unique spatal reference system ID (SRID)
– Numeric identfer
– No formal standard/catalog of SRIDs
– De facto standard: EPSG Dataset
● 4326 = WGS 84 (“GPS coordinates”)
● 3857 = WGS 84 / World Mercator (“Web Mercator”)
● A property of each geometry value
● Mixing geometries in diferent SRIDs in one computaton
doesn't make sense and will raise an error (also in 5.7)

● 5107 predefned SRSs from the EPSG Dataset 9.2 (MySQL
8.0.4)
– 4628 projected
– 479 geographic
● Exposed through an INFORMATION_SCHEMA view,
ST_SPATIAL_REFERENCE_SYSTEMS
● CREATE/DROP SPATIAL REFERENCE SYSTEM statements to
create your own

Example
CREATE TABLE cites (
id INTEGER AUTO_INCREMENT PRIMARY KEY,
name VARCHAR(20) NOT NULL,
loc POINT SRID 4326 NOT NULL
);
INSERT INTO cites (name, loc) VALUES (
'Trondheim',
ST_GeomFromText('POINT(63.43048320193547 10.394972698312927)', 4326)
);
INSERT INTO cites (name, loc) VALUES (
'San Francisco',
ST_GeomFromText('POINT(37.2726156666666667 -122.44254551944445)', 4326)
);

Functons
● Import
– ST_GeomCollFromTxt/ST_GeomCollFromText, ST_GeomCollFromWKB,
ST_GeomFromGeoJSON, ST_GeomFromText, ST_GeomFromWKB,
ST_LineFromText, ST_LineFromWKB, ST_MLineFromText,
ST_MLineFromWKB, ST_MPointFromText, ST_MPointFromWKB,
ST_MPolyFromText, ST_MPolyFromWKB, ST_PointFromGeohash,
ST_PolyFromText, ST_PolyFromWKB
● Export
– ST_AsBinary, ST_AsGeoJSON, ST_AsText, ST_Geohash

Functons
● Comparison
– ST_Contains, ST_Crosses, ST_Disjoint, ST_Equals, ST_Intersects,
ST_Overlaps, ST_Touches, ST_Within
– MBRContains, MBRCoveredBy, MBRCovers, MBRDisjoint, MBREquals,
MBRIntersects, MBROverlaps, MBRTouches, MBRWithin
● Produce new geometries
– ST_Bufer, ST_Centroid, ST_ConvexHull, ST_Envelope,
ST_MakeEnvelope, ST_Simplify, ST_Diference, ST_Intersecton,
ST_SymDiference, ST_Union

Functons

Functons
● Measures
– ST_Area, ST_Distance, ST_Distance_Sphere, ST_Length
● Extract propertes
– ST_GeometryN, ST_GeometryType, ST_InteriorRingN, ST_IsClosed,
ST_IsEmpty, ST_IsSimple, ST_IsValid, ST_PointN, ST_SRID,
ST_StartPoint, ST_X, ST_Y
● Helper functons
– ST_LatFromGeohash, ST_LongFromGeohash, ST_Validate, ST_SwapXY

Example
SELECT ST_Distance(
(SELECT loc FROM cites WHERE name='Trondheim'),
(SELECT loc FROM cites WHERE name='San Francisco')
) AS exact_distance;
exact_distance
8089891.633435546
SELECT ST_Distance_Sphere(
(SELECT loc FROM cites WHERE name='Trondheim'),
(SELECT loc FROM cites WHERE name='San Francisco')
) AS approx_distance;
approx_distance
8068723.414049273

Indexes
● R-tree indexes on spatal data
– Cartesian or geographic, depending on SRID
● Geographic R-trees in InnoDB only
● Used automatcally by the optmizer
– Triggered by use of spatal relatons (ST_Within, etc.)
– Cost based decision making

Upgrade Issues

Upgrade Issues
● YES, there are upgrade issues!
– We're sorry, but we have to …
● All EPSG SRSs are lattude frst, longitude second
– WKT and WKB input/output uses SRS axis order by default
● Can be overridden with 'axis-order=long-lat'
● Override opton not available in 5.7
– Earlier MySQL versions don't understand axis order, X=X and Y=Y
– Queries and/or scripts must be changed
● Storage format is stll longitude frst, lattude second
– Compatble with the limited geography support in 5.7

Upgrade Issues
● SRID 0 is the safe choice if using MySQL pre 8.0
– Set correct SRS afer upgrading
● Indexes must be recreated afer upgrade
– Column defniton must be modifed to use SRID restricton frst
● The SRID restricton is not available in 5.7
– Indexes on columns without SRID restricton will never be used
● Ignored by the optmizer
● Allowed to exist in order to preserve dump-restore compatbility
● Warnings will be issued

✓✓
Prepare Now
● Think through your use of SRIDs
– Use SRID 0 if you're unsure
● Use longitude-lattude ordering in 5.7
– But remember that import and export functons follow SRS defned
axis order in 8.0
● Use one SRID in each column
– Be ready to add SRID restrictons to columns and rebuild indexes in 8.0

Feature descriptons and design details
directly from the source.
https:/ppmysslsserverteamy.comyp

MySQL 8.0 GIS Overview

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