This document summarizes Andrew Collins' April 4th, 2005 presentation on MySQL Spatial Extensions. It outlines the OpenGIS Simple Features Specification geometry class hierarchy and spatial data model. It also describes some basic and spatial analysis methods defined in the specification, noting that MySQL implements some but not all methods. The document references additional OpenGIS specifications and the JTS Topology Suite library.

1. MySQL Meetup
MySQL Spatial Extensions
Andrew Collins
April 4th, 2005

2. Non-
Geometry Instantiable
Instantiable
Geometry-
Point Curve Surface
Collection
1+ 2+
Multi-
LineString Polygon MultiCurve MultiPoint
Surface
1+
1+
Multi- Multi-
Line LinearRing
1+ Polygon LineString
OpenGIS Simple Features Specification for SQL
Geometry Class Hierarchy

3. Point MultiPoint LineString LinearRing
Multi- Multi- Geometry-
Polygon
LineString Polygon Collection
OpenGIS Simple Features Specification for SQL
Spatial Data Model

4. SFS Methods : Basic
● GeometryType()
– “POINT”, “POLYGON”, “LINEARRING” ...
● Envelope()
– Polygon consisting of corner points of bounding box:
((MINX, MINY), (MAXX, MINY), (MAXX, MAXY),
(MINX, MAXY), (MINX, MINY))
● AsText()
– Returns string representation of the geometry in
Well-Known Text (WKT) format
● ... and a few other basic methods

5. SFS Methods : Spatial Relations
● Intersects(anotherGeometry : Geometry)
– Returns true if this Geometry 'spatially intersects'
anotherGeometry.
● Touches(anotherGeometry : Geometry)
– Returns true if this Geometry 'spatially touches'
anotherGeometry.
● Contains(anotherGeometry : Geometry)
– Returns true if this Geometry 'spatially contains'
anotherGeometry.
● ... and a few other spatial relational methods:
– Equals(...), Disjoint(...), Crosses(...), Within(...),
Overlaps(...), and Relate(...)

6. SFS Methods : Spatial Analysis
● Distance(anotherGeometry : Geometry)
– Return shortest distance between this Geometry and
anotherGeometry.
● Union(anotherGeometry : Geometry)
– Returns the point set union of this Geometry and
anotherGeometry.
● Difference(anotherGeometry : Geometry)
– Returns the point set difference of this Geometry and
anotherGeometry.
● ... and a few other spatial relational methods:
– SymDifference(anotherGeometry : Geometry),
Buffer(distance : Double), ConvexHull( ), ...

7. “Not Yet Implemented”
● The OpenGIS SFS specification is great, but...
– ... the spatial extensions are only available as of
MySQL 4.1.x
– ... and the SFS specification is not fully
implemented.
● Many of the spatial relations and analysis methods are
“not yet implemented.”
– This is understandable given the fact that “robust”
implementations of these methods are not easy to
create.

8. JTS Topology Suite
● The JTS Topology Suite

9. GML : Geography Markup Language
● Another OpenGIS specification used to format Simple
Features in XML
– XSLT available to translate GML to WKT
– ... and MySQL INSERT commands

10. Links
● Open Geospatial Consortium, Inc. (OGC)
http://www.opengeospatial.org/
● OGC: Simple Features - SQL (SFS)
http://www.opengeospatial.org/docs/99-049.pdf
● Spatial Extensions in MySQL
http://dev.mysql.com/doc/mysql/en/spatial-extensions-in-mysql.html
●
Geography Markup Language (GML3.0)
http://www.opengeospatial.org/specs/?page=specs
● JTS Topology Suite
http://www.vividsolutions.com/jts/JTSHome.htm