Is there a convenient way to create spatial index with Sqlalchemy or Geoalchemy?

Question

Yesterday someone told me that Geoalchemy was a good choice to support spatial extensions if I want to use Sqlalchemy. It really did good. Thanks for him a lot.

But I have not found a convenient way to create spatial index with Geoalchemy. Must I run this SQL directly?

CREATE SPATIAL INDEX sp_index ON my_class (
geom_col
);

Is there a convenient way to do it without directly writing the SQL?

Thanks!

Answer 1

When creating a table with table.create() GeoAlchemy will automatically create an index for the geometry column.

Also, SQLAlchemy Index instances have a create method. See the "Indexes" section in http://docs.sqlalchemy.org/en/rel_0_7/core/schema.html#metadata-constraints. I'm not sure if you'll be able to create a spatial index in MySQL with that but it's worth a try.

Answer 2

With GeoAlchemy, there are 2 steps you should take to create Spatial Index on the geometry column

• add attr 'spatial_index' to the geometry column
• Call the GeometryDDL extension

Example:

# note that spatial_index will set the column to not null 
class Building(Base):
    geom = GeometryColumn(Point(2, spatial_index=True))

GeometryDDL(Building.__table__)