OK, so it seems foreign keys are out. I am not a "master" programmer but
I think I have enough experience to accomplish this import. Therefore I
propose:
- Import data without foreign keys. Use previously described script, and
JOSM Conflation plugin to automatically handle 99.9% of cases.
Realistically this seems like the maximum that *any* automated system
can manage, regardless of programming knowledge. An advanced script does
not have local knowledge like I do. Both existing OSM data as well as
reference dataset have errors and omissions. If a 100% automated import
is required, then an import here is not possible.
- Use JOSM to manually handle the remaining 0.1% of conflation cases.
For these remaining issues, the deviations from reference data which
would cause problems with future updates are not marked using a foreign
key. Where necessary, perform on-the-ground checks to resolve conflicts.
- For future updates, there are multiple options:
- Only import areas which do not have existing good data. Since this
import's scope is currently limited to Cache Valley, UT, that means new
developments and expansion into farm land.
- Alternatively, when updating areas with older data (for example 10
years from now when parcels may have been divided, etc.), handle
conflation with previously imported data using a combination of
automatic matching and manual review, just like the initial import.
Thanks all for your input. I'll get to work right now updating the Wiki
page. Let me know what you think of these ideas.
Jacob
On 2022-10-11 07:25, Martin Koppenhoefer wrote:
sent from a phone
On 10 Oct 2022, at 20:25, Greg Troxel <[email protected]> wrote:
What I was trying to say is that without the benefit of experience of
getting all the way through an import, 2 years of living with it, and
contemplating an update import, foreign keys seem like they ought to
be
broadly useful. My impression from the list is that almost no one who
has that experience thinks so.
foreign keys are also harmful, at the extreme they may prevent a
contributor from performing an update because they do not know how to
deal with it, or prevent simplifying things by combining the geometry
(if everything is the same except the foreign key).
Cheers Martin
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