class Centroid(expression, **extra) Availability: MySQL, PostGIS, Oracle, SpatiaLite Accepts

class Transform(expression, srid, **extra) Availability: PostGIS, Oracle, SpatiaLite Accepts

class ForceRHR(expression, **extra) Availability:

class Length(expression, spheroid=True, **extra) Availability: MySQL, Oracle, PostGIS, SpatiaLite

class AsGML(expression, version=2, precision=8, **extra) Availability: Oracle, PostGIS, SpatiaLite

class MemSize(expression, **extra) Availability: PostGIS Accepts a single geographic

class AsSVG(expression, relative=False, precision=8, **extra) Availability: PostGIS, SpatiaLite

class SymDifference(expr1, expr2, **extra) Availability: MySQL (≥ 5.6.1), PostGIS, Oracle, SpatiaLite

class Union(expr1, expr2, **extra) Availability: MySQL (≥ 5.6.1), PostGIS, Oracle, SpatiaLite Accepts

class Difference(expr1, expr2, **extra) Availability: MySQL (≥ 5.6.1), PostGIS, Oracle, SpatiaLite