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Notes about personal GIS project.

Unless otherwise noted, all of these comments pertain to postGIS imports using osmosis


Don't know about other clients, especially free GIS clients, but Manifold System GIS client can work with a small window of a GINORMOUS postGIS table as long as there is a spatial (gist) index on the relevant geometry column. Some ramifications:

  • Because we can't create an index on Views, they are not very useful for large geometry datasets.
  • Although Manifold can perform it's own joins (e.g. between 'ways' and 'way_tags') within the client, because non-geometry tables have no spatial index, the client must import/link/cache the entire table.

This leads to the conclusion that we must de-normalize the data a bit into a structure closer to that of the simpler osm2psql tools.

Which attributes/columns do we want in the derived tables?

For the import, we want those columns required for:

  • ...rendering hints for the GIS client,
  • for validation/debugging of OSM/source data

For the eventual export back to OSM, we also want:

  • Attributes we might edit that need to be mapped back into our export.