[GRASSLIST:4984] Re: PostGrass Italian C driver
Radim Blazek
blazek at itc.it
Mon Nov 18 04:47:42 EST 2002
On Friday 15 November 2002 03:47 pm, Juanse wrote:
> Hi everyone
>
> I am a new comer onto Grass.
>
> I am migrating from Mapinfo stuff to OpenSource. I have succesfully
> migrated all my data to PostgreSQL/PostGIS and I can serv it with Mapserver
> (UMN), now I need to join Grass with PostgreSQL/PostGIS.
>
> Searching the web I have arrived to an italians students page decribing
> in detail a C driver call PostGrass, but I can only arrive to pdf files.
> http://www.rcost.unisannio.it/antoniol/students/PostGrass.
>
> I wonder if there is a place to download this driver or they come already
> installed on GRASS 5.1?
>
> Your help will be cordially wellcome
>
> TIA
>
> Juanse
> Temuko-Chile
PostGrass is in GRASS 5.1 sources and it should be compiled in downloadable
binary, BUT!!!:
1) Grass 51 is experimental version, not yet ready for users.
2) PostGrass is not fully compatible with PostGIS (Simple feature
specification) because Grass uses topological model for areas and
SFS does not. That means that it is possible to use lines and points
from one database in Grass and Mapserver, but not areas. PostGrass
is intended for multi user enviroments where more users must edit large
maps simultaneously.
3) For read only access to PostGIS, "fully" compatible (pseudotopology) with
SFS, OGR support (includes PostGIS) is planned, which will handle areas
also. This should not be difficult, shapefiles in Grass51 work in such
way, C interface in OGR was added and in fact one student already works
on that (I hope).
4) Note: it is not driver, PostGrass is optionaly compiled into vector
library and modules.
Testers are VERY welcome of course, but you must be patient and have enough
courage.
Radim
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