public StringExpression geometryType() {
        if (geometryType == null) {
            geometryType = Expressions.stringOperation(SpatialOps.GEOMETRY_TYPE, mixin);
        }
        return geometryType;
    }
Returns the name of the instantiable subtype of Geometry of which this
geometric object is an instantiable member. The name of the subtype of Geometry is returned as a string.

@return geometry type
querydsl-spatial/src/main/java/com/querydsl/spatial/jts/JTSGeometryExpression.java