[TCMUG] How do you match up two datasets?

[Ian Dees]

Wiping completely is an option, but it's still a bit complicated for two
reasons:
- It's slightly complicated to pick and choose which parts of an area you
want to wipe. There are services that allow you to grab all features of a
certain type in a bounding box which might make it easier, but for larger
counties it would require a bit more work.
- connecting the new data with the old data. Right now we have to manually
go through and find all the roads at the edge to connect to existing data.
Again, this would get quite a bit harder on busier/larger counties.

I'd love to see a county centerline dataset if you have one. I could try
this and see how hard these two steps are.

-Ian

On Thu, Aug 19, 2010 at 10:41 AM, Brian Fischer <bfischer at houstoneng.com>wrote:

> Ian,
>
> Coming at it from a time perspective, I would want to just to remove the
> old stuff and replace it with the new stuff.  There maybe a few cases where
> someone updated a road centerline in OSM that is not in the new GIS dataset,
> but in my opinion this would be pretty rare and it would take forever to
> compare each line one by one on an import.  The counties do a good job
> keeping the road centerlines accurate because they have to for E911
> purposes.  At least for horizontal accuracy, names and even address ranges.
> The exception might be if an OSM users adds a tag like speed limit.
>
>
>
> I would much rather see OSM have 98% of the road centerlines by correct for
> MN and see the update taking minimal time versus trying to compare every
> line for accuracy and having the process take years.  I only think this is a
> valid point for road centerlines.  I think there are other datasets that you
> would not want to take this approach in OSM like place of interest points,
> parks, buildings, etc.
>
>
>
> If you want me to get you a County road centerline file let me know, I’m
> sure I can come up with some county in MN (maybe Douglas, Rock or McLeod)
> that I could give to you.  This might be a good way to test your methodology
> for an import tool, at least with road centerlines.
>
>
>
> Just my 2cents.
>
>
>
> *Brian Fischer,* CFM  GIS Project Manager
> *Houston Engineering, Inc.*
> Phone: Direct: 763-493-6664 / W: 763.493.4522 / M: 763.229.2734
>
>
>
> *From:* tcmug-bounces at lists.osgeo.org [mailto:
> tcmug-bounces at lists.osgeo.org] *On Behalf Of *Ian Dees
> *Sent:* Thursday, August 19, 2010 10:29 AM
> *To:* tcmug at lists.osgeo.org
> *Subject:* [TCMUG] How do you match up two datasets?
>
>
>
> Hi TCMUG,
>
>
>
> I've been pondering a way to help people import into OSM while respecting
> the existing data. To that end, I'm wondering if anyone on the list could
> talk about how they would go about applying one (newer, presumably better)
> dataset to another. I'm thinking of the usecase where MetroGIS has old
> street centerline data from 1990 and receives an update from 2010. How would
> you go about doing that? What tools would you use and what are they called?
>
>
>
> I'm envisioning a web map that allows you to view the new data as an
> overlay on the existing data, marking whether or not to import each new
> feature and how the import should happen (completely remove old stuff and
> replace with new stuff, update the metadata on the old stuff with the new
> stuff, or something else). However, when there are a gazillion things to
> import, it might not make sense to do that one-by-one.
>
>
>
> Thanks for your thoughts!
>
> Ian
>
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