[Talk-tz] Import of Tanga Building Footprints

Mon Jun 14 13:56:02 UTC 2021

I would like to thank you, Innocent Maholi for taking time and passing through our proposal about OSM Data Import, Furthermore on the Africa QC Project, I went through and found that it is the awesome work you guys are doing, congratulate once again.

On the concern you posed about the Tanga Building Footprint Import were very interesting, We have taken all your views and we are working on them to make sure that these datasets are public available and utilized to maximum therefore we would like to respond to them respectively:

  *   We are aware of the slight changes that might be there between the digitized data from the 2019 satellite image to date, but we are both aware of the growth rate of Tanga City as compared to other cities in Tanzania, thus, the following changes will be handled as we explained in our OSM WiKi page that we shall have microworks aligned with this import to handle such differences and enriching these datasets in the near future.
  *   We initiated this discussion to generate public to engage with more contributors who will have interest in volunteering when the upload starts. The project is going to be shared using the HOT Tasking manager where experienced mappers from ARU are going to work along with the community members who have interest to enrich the community. It is our belief that OMDTZ has a lot of experienced and we will be very happy if they show interest, we can loop their emails when data import activity starts.

The best approach when import starts is manually whereby the community, and ARU Students with data split in a number of files, that will correspond to an equal number of projects in the HOT Tasking Manager.
This is to ensure that:

  1.  Any volunteers may join the import effort, at any time (although only skilled mappers should join).
  2.  We can check, at any time, the mapping progress of the import.
  3.  We can easily validate each task too and check the validation progress.
  4.  Easy to set up.

  1.

Antidius Kawamala
GIS Specialist and Researcher (dLab)
M: +255769806836
Founder of RootGIS<https://rootgis.wordpress.com/>
Skype: Antidius Kawamala | Twitter: @Antidius36
P.O. Box 33335 Dar es Salaam, Tanzania | College of ICT, UDSM- Kijitonyama campus | dLab <https://dlab.or.tz/>
[cid:1dd4c857-d9c5-4758-8acd-8e7a3307c7bb]

________________________________
From: Innocent Maholi <innocentmaholi at hotosm.org>
Sent: Friday, June 11, 2021 6:34 AM
To: Antidius Kawamala <antidius at dlab.or.tz>; Omar Bakari <omar at dlab.or.tz>; namangaya at gmail.com <namangaya at gmail.com>; Ibrahim Msuya <imsuya at ihi.or.tz>
Cc: talk-tz at openstreetmap.org <talk-tz at openstreetmap.org>
Subject: Re: [Talk-tz] Import of Tanga Building Footprints

Hi Antidius and team,

Thanks for opening up communications about the data import intended for Tanga and for sharing the link to the wiki page with the workflow. I'm also adding a few other people to this email chain.

I have downloaded and checked the Tanga buildings data<https://drive.google.com/file/d/1zzuKwMvZCK6_J-_HK8k2eH9KkaADyUrW/view?usp=sharing>, this generally looks good and I’d like to congratulate everyone involved in the digitization process however a few things stood out to me;

  *   The use of 2019 imagery seems to be off for digitization as 2 years of difference can present outdated data that allows lots of differences with the current situation. Correct me if I’m wrong but I understand that ARU/dLab has access to 2021 drone imagery of Tanga which seems to be perfectly up to date for this work. Did you consider this option?

  *   The data doesn’t show differentiation between “complete buildings” and “incomplete/unfinished buildings” even though the difference can clearly be visible (at least with the Bing imagery I have used). This is of interest for data users to understand and make considerations.

Now coming to the OSM data import, this is usually a complex process as it needs to be properly conducted and reviewed with the assistance of more technically oriented and experienced OSM editors to avoid data quality issues and conflicts while keeping the OSM data at its best state. Reading through the Tanga wiki page<https://wiki.openstreetmap.org/wiki/Tanga_Building_Footprints_Import> you established, here’s are a few (not all) comments;

  *   There’s no clarity on the workflow between the building data you already created and the methodology to have this data in OSM. While the import type<https://wiki.openstreetmap.org/wiki/Tanga_Building_Footprints_Import#Import_Type> section talks about how the community will use the HOT tasking manager to import this data to OSM, the team approach<https://wiki.openstreetmap.org/wiki/Tanga_Building_Footprints_Import#Team_Approach> section suggests that “data import will be conducted by the University experienced OSM mappers through existing OSM project accounts (Living_Lab_Initiative)”. As this contradicts itself, does this data import neglect the broader OSM community and its contribution? Do the intended university students have (enough) experience with large-scale imports like this?

  *   The use of HOT tasking manager as suggested isn’t quite captured in the “workflow” section. This part only mentions JOSM, OpenData plugin, ToDo plugin, and OSM only as the tools/platforms to be used for this import. This worries me whether there's a clear and understandable workflow to be used for this.

  *   QA plans are not quite well established to ensure the good quality of the data. The wiki suggests that “Validation of the import will be done by a second user in the Tasking Manager”. Who is this second user? Is it global OSM contributors? Of what mapping level? Can they be trusted with QA? etc.

OSM guidelines suggest that “Take great care to avoid damaging the database and don't leave a messy import and assume that nameless OpenStreetMap contributors working in iD<https://wiki.openstreetmap.org/wiki/ID> and Potlatch<https://wiki.openstreetmap.org/wiki/Potlatch> will tirelessly complete your work. JOSM is better at untangling messy data, but it's still difficult and you should do this work yourself if necessary.” Of all things, QA should be given high priority to ensure good data.

  *   Last but not least, this import should be registered in the import catalogue<https://wiki.openstreetmap.org/wiki/Import/Catalogue> as it is missing there right now.

My honest opinion is that this import is not quite ready to be executed with the plan that is in place. The data is quite good and of decent quality but the process does not ensure keeping OSM without risking the data quality in the database. I'd appreciate hearing more thoughts from you and the mailing list members.

Thanks and regards,

----
Innocent,
Phone: +255 714 166 665 (Call & WhatsApp).

On Wed, Jun 2, 2021 at 9:08 PM Antidius Kawamala <antidius at dlab.or.tz<mailto:antidius at dlab.or.tz>> wrote:
Hello community,
The subject of this message is to inform the OSM community in Tanzania
of an import prepared by Living lab initiative as part of a project to scale up the Open Street Mapping project,Missing Maps Initiative by combining data obtained from manual digitization from the latest satelite image 2019 In Tanga City.

This import consists of more than 500 hundred thousand footprints of buildings located in all over the Tanga region.

A wiki page with details of the proposed import is available
here: https://wiki.openstreetmap.org/wiki/Tanga_Building_Footprints_Import

Experienced OSM contributors who would be interested in participating in
this import will be welcome.

A similar message regarding this import will also be shared on the OSM
mailing list,HOT and WhatsApp group for OSM Tanzania after posting to the wiki to gather a maximum feedback.

Don't hesitate to share your comments, questions, or problems
related to this import before it begins.

Regards

Antidius Kawamala
GIS Specialist and Researcher (dLab)
M: +255769806836
Founder of RootGIS<https://rootgis.wordpress.com/>
Skype: Antidius Kawamala | Twitter: @Antidius36
P.O. Box 33335 Dar es Salaam, Tanzania | College of ICT, UDSM- Kijitonyama campus | dLab <https://dlab.or.tz/>
[cid:179f919e31b8cd131381]

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