Hi Marco,

On Tue, Feb 23, 2010 at 12:08 AM, Marco Lechner - FOSSGIS e.V. <
[email protected]> wrote:

> Hi Brett,
>
> thanx for your answer.
> I thought using completeWays=yes and completeRelations=yes takes care of
> nodes outside my bounding polygon.
>

Those options will fix the problem, but they are horrendously slow.  If they
work for you then that's fine, but most users avoid those options if at all
possible.


>
> 1. If a node is created new it will be inside my merged osc and
> therefore be inside my patched AOI.osm and (if part of a way or
> relation) put in my recently cutted AOI.osm
>
Correct.

> 2. If a node is deleted it will be deleted by patching the merged osc
>
Also correct.

> 3. the only problem seems to exist if an existing node outside the
> polygon is changed and integrated into a way or relation inside my AOI.
> Because the node doesn't exist in my AOI (also not in the patched AOI
> before cutting it again), because it isn't created freshly. Am I right?
> Or are there situations I miss?
>
Yes, also correct :-)  Well kind of anyway.  If the node is modified as well
as the newly containing way or relation then it will be available for
inclusion (if you're using completeWays or completeRelations anyway).  But
if the node is not modified but it is added to a new or existing way or
relation then it cannot be included.  However if you're not using the
completeWays and completeRelations options then it will never be included
regardless of scenario.


>
> I'm very interessted in creating a consistent regionally bordered OSM-DB.
>

Creating a perfect bordered extract is not simple.  But you do have a couple
of options:
1. Load the complete planet (or at least an area somewhat larger than the
one you require) into the Osmosis "simple" schema via the --write-pgsql-dump
task, then use the --read-pgsql and --dataset-bounding-box task to extract a
perfect extract including all required nodes.  Keep the database up to date
with minute changesets and the --write-pgsql-change task.
2. Create the extract in two parts.  First part is to extract a region from
the overall planet that is larger than your required area, but small enough
to keep the result file small.  Do this with the default --bounding-box
task.  Then run the --bounding-box task over the smaller result file with
completeWays and completeRelations both enabled.  I haven't tried this
myself, but I think it should work.

It's not a simple problem unfortunately, and unless you have a really really
good reason to make the extract correct, it's much simpler to make some
compromises.

Brett
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