[postgis-users] building a vmap db

[Randy George]

Hi,

	I've done a few translations of vmap0 over the years but I have not
tried it into PostGIS yet. This would be a useful effort. I imagine it would
be beneficial to keep vmap0 separate from vmap1 at least in a separate table
set if not a separate db. I have not used ogr2ogr for vmap so I don't know
how the output is organized. For sure it would be best to merge the four
continental categories into a single db. You would want to work out a way to
eliminate the duplicate features in the continental overlaps. These were not
consistent in the early vmap0.

Perhaps tables like this would allow layer separation by feature type.
Db vmap
Vmap0_dn	vmap1_dn
Vmap0_po	vmap1_po
Vmap0_pp	vmap1_pp
   .		   .
   .		   .

Alternatively:	db vmap0	db vmap1
			  dn		   dn
			  po		   po
			  pp		   pp
   			  .		    .
   			  .		    .

  What would be the relative performance hit for placing all features in a
single table with feature layers identified by field rather than as
separated db/tables? This is not a huge amount of data. As binary dwg it was
around 650Mb which I'm guessing would be comparable in PostGIS.
	Text label points would require additional fields for size,
rotation, and text value so at least these would probably be easiest kept as
a separate table. As I recall there are some classification code differences
in the other feature categories as well, which might require some
complications. (some codes had subset codes with subset codes)

It would be interesting to hear other peoples' experience.

Randy

-----Original Message-----
From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of Mike
Jackson
Sent: Sunday, October 24, 2004 10:46 AM
To: postgis-users at postgis.refractions.net
Subject: [postgis-users] building a vmap db

Hi,
  Has anyone built a whole-earth postgis db with vmap0 and the available
vmap1 datasets?

  I am planning to build one, and am now wondering what is the best approach
to organize the data, 
e.g. vmap0 having 4 seperate databases or just 1, etc. What about combining
vmap0 and vmap1 all 
into one single database? What I basically am after is the answer to "What
makes the most sense 
from the postgis perspective". I will want to create spatial indexes for as
much as possible.

  So far, I've experimented with importing the vmap0 eurasia dataset with
ogr2ogr. If anybody has 
built the whole database and would share notes with me, I would be very
grateful.

Thanks,
Mike
_______________________________________________
postgis-users mailing list
postgis-users at postgis.refractions.net
http://postgis.refractions.net/mailman/listinfo/postgis-users