[OSM-dev] MySQL GIS extensions - some tipps

[Marcus Wolschon]

On Wed, Jul 22, 2009 at 4:25 PM, Andreas Kalsch<andreaskalsch at gmx.de> wrote:
> I don't render maps with it, so I don't know how it scales. But Mapnik
> will connect easier to Postgres/PostGIS. I will outsource rendering for
> my project.

Note: I don`t use Mapnik. I was talking about _interactive_ rendering.
It`s a routing-application and I`m just testing if offering MySQL as an
additional supported local map-format works out. Other offered
formats are OsmBin, the H2-embedded database, xml-files (for testing),
in-memory, ....

>> Can you decompose a POINT into lat+lon in an SQL-query?
>> If not, how much space is wasted by having all coordinates
>> twice?
>>
> Yes.

Yes - you can decomposit them or
Yes - you have to store a Point AND Lat+Lon as separate columns?

> But I just put relevant features into the geo database - I save
> nodes and ways which have relevant tags, and relations as
> GeometryCollections and MultiPolygons. It makes no sense to put nodes
> and ways into the GIS table, which are just parts of ways/relations and
> do not play an own role. Result: 5 of 17.3 GB (for Europe) is for GIS
> data. I use the GIS table for analysis and re-computing. It pays off.

How much would that be without filtering? Since I have no clue what
are "relevant tags and relations" for you.

Marcus