[gdal-dev] OSM driver to create separate tables for tags

[Jukka Rahkonen]

Hi,

I wonder if it would make any sense in the GDAL context to have an option in
the OSM driver to separate geometries and tags and write them into their own
tables. The structure of the resulting tables (5 + 5 for points, lines,
multilines, multipolygons and relations) would be like:

Geometry table
==============
osm_id (long)integer or string (primary key)
geometry geometry

Tag table
=========
tag_id (long)integer or string (primary key)
osm_id (long)integer or string (foreign key)
tag string 255
value string 255

I am remembering that OSM has a 255 character limit for tags and values but
I am not sure.

This way all the data from OSM could be converted without any loss into any
database and into CSV and why not also into shapefile + additional dbf file
for tags. That would make much sense for those who are using and especially
analyzing OSM data because all the tags would be are reserved and they could
be queried simply with standard SQL. However, almost everything else in
GDAL/OGR is based on simple features and pushing OSM data into relational
model may not suit for the engine we have.

Utilization of these tables in GIS would not be too complicated at least for
read-only access. It would be best to create views or tables from the master
tables for creating fixed schemata for the work layers but that's all.

-Jukka Rahkonen-