Re: [osm-nyc] Bicycle Parking points

From: Chris M.
Sent on: Wednesday, July 18, 2012 12:16 PM
I'm a little confused by meetup.com, I thought this was a discussion
thread in our discussions space on meetup. I hope I am not spamming
everyone. Perhaps we should move our discussions there.

NYC is more open with their data these days. Check out this quote from the page

http://www.nyc.go...­

"Opening data to the public and developers is an important part of
DOT's online initiatives"



On Wed, Jul 18, 2012 at 11:51 AM, Chris Mcnally <[address removed]> wrote:
> I don't know if there are easy answers to your questions. If you do an
> import once, then users manually add more nodes of the same time, then
> if you try to import again you are going to create duplicates.
>
> If you think the city data is up to date and accurate, then you could
> delete old nodes and import the entire set. There are other options,
> you might be able to use RackID that the city uses, or simply date, to
> eliminate some duplicates, but it would have to be an iterative
> process using JOSM to verify that the the import would be correct.
> Maybe it would be a neighborhood by neighborhood task.
>
> Maybe I should have send I would attempt it with care because I think
> the city data is more rich than the survey data.
>
>
>
>
>
>
>
>
> On Wed, Jul 18, 2012 at 11:11 AM, Serge <[address removed]> wrote:
>> Chris,
>>
>> Thanks for the feedback; your real world experience is really vital to this discussion.
>>
>> It took me a long time to really have a solid grasp on why imports are so problematic,
>> but you've touched on a few of the prominent reasons, so I want to explore it a
>> little.
>>
>> On Wed, Jul 18, 2012 at 10:53:28AM -0400, Chris Mcnally wrote:
>>> That is because as of 2009, there may have only been one or two racks, but 2010 and
>>> 2011 were big years for bike rack installation.  I noted that node[masked] was
>>> accurate, and also contained some good info about the size of the rack and node
>>>[masked]­ is accurate but it says 24 West 13th street, and I am not sure if that is
>>> correct.
>>
>> Given what you've said, what's the right thing to do?
>>
>> Do you make a new bike rack node?
>>
>> Do you fix the existing node?
>>
>> Do you do something else entirely?
>>
>>> I have been adding and editing bike rack location in NYC for months now and I can
>>> tell you if the DOT would update their data it would be so much easier for me to
>>> import it.
>>
>> If you re-import the DOT data, you now have to do conflation, and this is where OSM
>> and imports really fail.
>>
>> So let's say that in the above case, you made a new node representing the bike racks
>> you found.
>>
>> How will the import process know that your data (the node you added) is present?
>>
>> Using more technical language "What can we use to conflate the two datasets?" and once
>> you do conflate them, what do you do if there's a difference in the data? Eg you've
>> said there are 4 bike spots, but the DOT data says there are 2?
>>
>> So if you aren't sure what the right answer is, then do you make changes at all? That
>> is, knowing there's going to be an import may actually de-incentivize you from making
>> the change yourself!
>>
>> Further complicating the issue, even between governmental datasets, it's often the
>> case that the IDs are not kept between processes. That is ID 1000 in dataset 2012 may
>> not be the same object 1000 as it was in dataset 2009.
>>
>> It's a real mess, and it's why a lot of old timers like myself are pretty down on
>> imports.
>>
>> - Serge
>>
>>
>>
>> --
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>> This message was sent by Serge ([address removed]) from OpenStreetMap NYC.
>> To learn more about Serge, visit his/her member profile: http://www.meetup...­
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>
>
>
> --
> Please Note: If you hit "REPLY", your message will be sent to everyone on this mailing list ([address removed])
> http://www.meetup...­
> This message was sent by Chris Mcnally ([address removed]) from OpenStreetMap NYC.
> To learn more about Chris Mcnally, visit his/her member profile: http://www.meetup...­
> Set my mailing list to email me
>
> As they are sent
> http://www.meetup...­
>
> In one daily email
> http://www.meetup...­
>
> Don't send me mailing list messages
> http://www.meetup...­
> Meetup, PO Box 4668 #37895 New York, New York[masked] | [address removed]
>

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