[pgrouting-dev] Questions about pgrouting dijkstra output table

Angela Pappagallo angelapappagallo at libero.it
Wed Nov 24 05:30:03 EST 2010

Dear all,

I've just signed to this mailing list even if I would have done it before!
I've started using pgRouting only some months ago, when I needed to 
calculate shortest path on a very huge size graph, that required too 
much memory and cpu to be loaded and processed into my own application.  
pgRouting helped me to move complexity of representation and calculation 
from RAM to a geospatial database. So I 'm really grateful to pgRouting 
community :-)
While using pgRouting (pgRouting-1.03) I've encountered only the 
following problem:
as you know the shortest path calculated by dijkstra is stored in a 
table called "dijkstra_result" and containing "MULTILINESTRING" kind 
objects.  That is shortest path consists of more multilinestrings. The 
matter is that multllines  are not stored into the order I expected. In 
fact it's not always true that first table record  contains first 
multiline (containing first point) of shortest path, and the other 
multilines are not stored so that one record multiline is the next, in 
the expected order, of the previous record multiline.
This is not a problem if*dijkstra_result * table has to be used only as 
a layer to be visualized. But if I need to load into my 
application*dijkstra_result* table content and rebuild shortest path, 
for example by considering all its points coordinates, I need to order 
multilines, and that's what I've done :-)

I wonder if this feature is to be considered a bug or if it has never 
been a problem before.

I apologize for being so long.

thanks in advance

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