[postgis-users] Question

[Simon Greener]

Martin,

> Here's some ideas for areas where I think there is a significant
> difference between Oracle and PostGIS
>
> - Oracle's tolerance-based precision model VS ??? in PostGIS

Yes, this is an important area that is poorly understood even by Oracle users. What can one say, in summary, about PostGIS's precision model?

> - 3D support

Indeed.

I don't wish to make the presentation a comparisonfest - for example Oracle has more complete implementations (if one comparatively examines the APIs) of LRS, Network analysis, Topology and GeoRasters. Rather I want to talk about how one would approach either product given experience in the other.

> - Geodetic data support

This is an interesting area especially given the development of a new geography data type in PostGIS. Am I right in saying that there is very little support in the OGC or SQL/MM standards or a geography data type?

> - robustness (may be hard to provide examples, but I have seeen some
> fairly simple functions (eg buffer) completely kill the Oracle
> instance.  PostGIS no doubt has its own failure modes)

This is an area in which PostGIS shines now that the new, improved, ST_Union aggregate operator has been released. The performance is far, far faster and more robust than Oracle though I cannot release comparative performance figures gathered from my own testing. PostGIS has a range of excellent, robust geoprocessing functions that are sorely missed in Oracle for simple, vector data (particularly polygon) processing.

> - external tools for loading and viewing spatial data

I would say that Oracle has far more tools supporting loading and viewing than PostGIS but perhaps I am not aware of those that support PostGIS and not Oracle.

regards
Simon
-- 
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