[GRASS5] Problems with vector import, and a suggestion

David D Gray ddgray at armadce.demon.co.uk
Sun Feb 10 19:46:14 EST 2002

Radim Blazek wrote:

> On Friday 08 February 2002 20:17, David D Gray wrote:
>>There is the possibility of storing topology with PostGIS (or by means
>>of another extension). Perhaps in 'hidden' fields (attributes). Has
>>there been any discussion on this?
> No, was not discussed. It is probably possible, but it is not build in PostGIS
> now. They want support topology, but we cannot wait for that and
> I am not able write that 'another extension'.
> I think that we can use grass topo until topo in PostGIS is available.
> Saving grass topo in database is not advantage.
> Do you know about any existing solution?
> Radim

Not apart from that we discussed (a long time ago), the possible fields 
you might include in a database to support topology on a subset of 
geometric objects that include lines (arcs), points and rectangles 
(MBR's) but not polygons or anything more complex. These would be 
constructed through index lists, as is done in GRASS, but here we may be 
able to better employ table joins and other DBMS features to better 
query or process the dig_plus equivalent. But it is as you say, 
something for the future (GRASS 6+ ?)


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