[Imports] Import building footprints Lopa & Lingo

Jorieke Vyncke jorieke.vyncke at london.msf.org
Wed Jul 22 09:23:14 UTC 2020


Hi Matheusz, Jo and all,

The import will certainly not be an automatic dump. But it will not be done through the Tasking Manager, but by just coordinated between myself and some other experienced mappers from the Missing Maps community directly through JOSM. But indeed by splitting up the data in chunks of 500 buildings we are able to check the data in detail before uploading it. The todo plugin is indeed a good suggestion.

Further I am a bit confused, if we would have been able to digitize the data from the imagery we would have done so. We have done this already in the places surrounding the data we have available here for the Lopa & Lingo area. See here: https://www.openstreetmap.org/way/820347035#map=14/1.7331/30.4503 However now we have this good quality dataset that is created on imagery of January 2020, which is several years more recent than we have available for usage on OpenStreetMap and we would not be able to use that on OpenStreetMap because we cannot verify this data with imagery on OpenStreetMap?

So trying to convince you again why in my opinion it is a good quality dataset:

  *   We have been working with Salzburg university for years and they have delivered good quality work for years to support our activities. Check some of their work here: https://zgis.at/
  *   The methodology Z gis has used is semi-automatic. This means that all automatic extracted buildings were validated by visual interpretation and buildings have been added manually to the dataset where needed.
  *   Many of the buildings of the dataset do overlap exactly with buildings on the older imagery that we have available for usage on OpenStreetMap, and with the already existing buildings onto OpenStreetMap.
  *   There is a very low risk in features ‘not representing anything real’. The exact geometry is mostly not that important for the usage of the data for us – this in contrary to the indication of the existance of the building and the material it is made off.

So yes, there might be a slight issue with the geometries of a small number of buildings, but this is thus because of written reasons in my opinion something we can fix by the manual treatment of the data.

So what do others think?

Would the situation change if myself and the few volunteers working on uploading the data could have access to the initial imagery? I think that might be maybe possible…  Of course if there are experienced mappers here who would like to help out with the import, please let me know, you’re always welcome to join the effort!

Btw, thanks to challenge me. I hope we can come to a good solution here together?

Thanks,
Jorieke



From: Mateusz Konieczny via Imports <imports at openstreetmap.org>
Sent: 21 July 2020 13:04
Cc: imports at openstreetmap.org
Subject: Re: [Imports] Import building footprints Lopa & Lingo

As I understand, the plan is to load the buildings in manageable sets from the tasking manager,
and person doing verification will skip solely clearly bizarre geometries and assume that everything
else is correct.

I think that given presence of nonsense geometries means that seemingly OK ones cannot
be assumed to be valid ones, and only verified ones should be imported.

Jul 21, 2020, 11:53 by winfixit at gmail.com<mailto:winfixit at gmail.com>:
I get the impression Mateusz thinks the import will consist of an automatic dump of the data, whereas the actual plan is to load the buildings in manageable sets from the tasking manager and then a person does the verification, maybe by using the todo plugin in JOSM?

Polyglot

On Tue, Jul 21, 2020 at 10:25 AM Jorieke Vyncke <jorieke.vyncke at london.msf.org<mailto:jorieke.vyncke at london.msf.org>> wrote:
Hi Mateusz,

Thanks for your feedback!
There are really not that many of this type of buildings in the dataset, most of the buildings are nicely squared or circulized. By the manual verification of the data, we’ll of course compare and adapt the building data with the latest imagery that we have available on OpenStreetMap – the Maxar Premium Imagery. We’ll correct with help of that imagery and of course in all cases nicely square corners of the weird shapes. There will really not be a ‘soul-crushing cleanup’ needed after this import.

Would you rather propose to leave these buildings out? We could do that as well, but I would prefer not to, since this means we will have an incomplete dataset in the area. I’d rather choose for correcting the shapes with help of available imagery.

Best wishes,

Jorieke



From: Mateusz Konieczny via Imports <imports at openstreetmap.org<mailto:imports at openstreetmap.org>>
Sent: 20 July 2020 18:20
Cc: 'imports at openstreetmap.org<mailto:imports at openstreetmap.org>' <imports at openstreetmap.org<mailto:imports at openstreetmap.org>>
Subject: Re: [Imports] Import building footprints Lopa & Lingo




Jul 20, 2020, 18:18 by jorieke.vyncke at london.msf.org<mailto:jorieke.vyncke at london.msf.org>:
Q: Some buildings have strange trapezoidal shapes, how are you planning to correct them without accessing the imagery?
There are not that many of these. Since we are not able to check back with the original imagery, we’ll have to trust the dataset we want to import for this and will upload the data. Of course by looking at the data manually we would be able to spot areas with real issues with this and then we can still decide to not upload that data.
So clearly suspicious shapes such as this trapeizodal ones will be skipped and
everything else without blatant mistakes will be imported without verification?

That seems to be a bad idea and I am opposed to such import. It will just burden
any community of mappers that may appear with soul-crushing cleanup.
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