[Aust-NZ] Portable geospatial file formats (was: Live CDs for the FOSS4G conference and DebianGIS)

Robert Coup robert.coup at koordinates.com
Fri Apr 18 01:01:34 EDT 2008

On Fri, Apr 18, 2008 at 3:52 PM, Hamish <hamish_b at yahoo.com> wrote:
>  It is good news that we don't have to start from shapefiles, they may be
>  universal but parts of the format (DBF) are lossy and unnice.

I think we're all agreed on that. What are the alternatives?

We can represent data nicely and openly in:
 - GML
 - SQL - oracle, mysql, postgres, mssql, ...
 - KML (ish)

But people can't *use* raw SQL or GML/KML - they're
transfer/interchange formats. (well, you can use GML/KML but you don't
get spatial/attribute indexing or efficient access unless your system
RAM >>> data-size)

Postgres and/or SHP seem to be the 'native' formats of most OSSG apps
- where they work most efficiently. But it seems unreasonable for
everyone to need a PG server to do some work.

This was brought up on the PostGIS lists this week:

Basically SpatiaLite adds a geometry type to SQLite via an extension:
 - sqlite DBs are just a single file. easy to transfer and portable across OSs
 - WKT & WKB, core of the SFSQL functionality, and they're working on more.
 - reprojection via proj4
There's some other people looking at spatial indexes based on R-Trees
for sqlite, but the link escapes me right now.

I see the benefits of using SQLite as a 'single-compact-data-store' format:
 - open
 - efficient (indexing)
 - portable (cross platform, supported by every development language alive)
 - supports multiple layers
 - relational - this may be a drawback depending on your POV ;)
 - can mix spatial and non-spatial data tables
 - compact

It wouldn't have the performance of Postgis/Oracle but could provide a
modern replacement for the Shapefile.

What am i missing? What do you all think?

Rob :)

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