[Aust-NZ] Live CDs for the FOSS4G conference and DebianGIS

Robert Coup robert.coup at koordinates.com
Thu Apr 17 19:38:18 PDT 2008


On Fri, Apr 18, 2008 at 2:00 PM, Hamish <hamish_b at yahoo.com> wrote:
>  sounds reasonable enough, and fairly cheap if we want to avoid dealing
>  with a reseller. (But it sounds like Rob is willing to provide the raw
>  data)

Realise that the Cadastral/Topo stuff from LINZ are in proprietary
ASCII formats, so they can't just be loaded into PostGIS or uDig. And
Cadastral stuff is a DB dump - its 80+ tables (iirc) with only a small
spatial component.

>  The BDE website says the dataset is now 30GB; I remember the old copy of
>  linz_topo4 shapefiles just fit on a 4gb DVD. ... so how big are we
>  looking at? Will we have to pick selected layers and/or generalize them
>  into smaller files to fit on a DVD?

topo data is ~4.5GB as shapefiles, but includes semi-irrelevant stuff
like label points and boundaries of polygons as linestrings. At
Koordinates we've normalised the cadastral stuff into some 'themed'
layers - addresses (1GB), parcels (2GB), titles (1GB), etc by plucking
selected stuff from the DB tables. About 50% of the cadastral data
isn't relevant for most people - survey marks & observations.

>  > Next steps are to figure out an import process that would allow for
>  > future updates,
>
>  maybe too far abstracted and the problem at hand is organizational; but for a technical solution you might look at how the IHO's S-57 electronic nautical chart format deals with periodic updates to the dataset. (via amendment patches)

Thanks, I'll have a look. OSM is versioned, but we want to improve on
LINZs data but at the same time be able to replace stuff with what
LINZ has been improving offline. OSM has had some bad experiences with
'bulk' imports before (TIGER) so it'd need to occur in a structured
but incremental fashion too.

Rob :)



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