[Talk-ug] Import of Buildings in Districts Bordering DRC

Thu Jul 9 19:07:59 UTC 2020

Hello Deogratius,

First of all, great project, really looking forward to get going.

I went through both wiki pages, and overall very solid and detailed
approach.
I do have some concerns, points on which improvements could be made.

1) Offsets - in many previous HOT projects offsets were provided by the
project manager, which are easy to store and implement in JOSM. Until
November 2019 we could use the MAXAR imagery in JOSM (still blocked ?
only Maxar imagery in ID), and I used it a lot.  My experience was that
it has significant offsets in comparison with other imagery layers,
especially on hill sides you see a lot of distortion.  This can even be
seen in the offset of roofs in regard to the ground level.  An important
issue in correct alignment of the imagery.
So when you state in the procedure that we should align the layers by
looking at the buildings this will not be correct.  On a tile by tile
basis you should align with features on ground level, most convenient
are roads.
Another way could be we have GSM tracks or reference points from the
field.  The project manager could make offsets available for every tile
using these field datasets or you could engage some people in the field
to get them.  Because even many of the existing buildings could be
misaligned.

2)  How to determine which data is the most recent.  The Maxar imagery
is dated. Other imagery layers on which existing buildings are mapped is
mostly not.  SO there is no clear reference of what is most recent. 
Comments and descriptions in changesets can provide some information, as
many existing mapping is done based on field knowledge. So some
improvement and more details could be provided in the procedure on how
to determine which is the most recent and accurate data by referring and
evaluating data in the changesets.
Same applies to building relations when 3D mapping was done.  You should
provide some details there that in these cases only the building outline
should be replaced and other building:parts should be updated.  There
are not many but some are there because I added them.  This is a very
complicated task.

3) Replacing building geometry.  Will be a much more extensive exercise
as described.  Many areas are far more detailed then just the
buildings.  As you probably know many have the plots aligned with
landuse tags, other features as fences and gates are present at many
locations.  If you replace the geometry with the new buildings all these
"attached" features, some even sharing nodes with the building, must be
updated.  I have no experience with geometry replacement so how will
this work ?  If a misalignment is seen all the features need to be
aligned as a group.

4) Currently there are two UN mapping teams doing a lot of work in these
areas, in support of MONUSCO troops. One focuses on roads and buildings,
the other team on landuse.  How do we avoid conflicts with those
projects or get them involved ? They contacted me several times so they
are open for cooperation.

Greetings and success with the project.

Bert Araali

On 02/07/2020 17:46, Deogratias Kiggudde wrote:
> Hello community,The subject of this message is to inform the OSM
> community in Uganda of an import prepared by HOT [1] as part of a
> project to scale up the Missing Maps initiative, combining data
> extracted in a way automated and information collected in the field
> [2].In the Uganda , this import consists of more than 2 million
> footprints of buildings located in the districts of Kisoro, Kanungu,
> Rubirizi, Kasese, Bundibugyo, Ntoroko, Bulisa Hoima, Kikuube, Nebbi,
> Zombo, Arua, Koboko, Maracha, Kiryandongo, Kamwenge, Kyegegwa and
> Insigiro. This data was extracted from high-resolution imagery
> provided by Maxar over the period 2015 to 2019.
> A wiki page with details of the proposed import is available here:
> https://wiki.openstreetmap.org/wiki/FR:Import_B%C3%A2timents_Maxar-Ecopia_Est_RDC_%26_Ouest_Uganda <https://wiki.openstreetmap.org/wiki/FR:Import_B%C3%A2timents_Maxar-Ecopia_Est_RDC_%26_Ouest_Ouganda>
> A second page contains the practical details of the proposed
> methodologyto perform this import:
> https://wiki.openstreetmap.org/wiki/FR:Import_B%C3%A2timents_Maxar-Ecopia_Est_RDC_%26_Ouest_Ouganda/D%C3%A9roulez <https://wiki.openstreetmap.org/wiki/FR:Import_B%C3%A2timents_Maxar-Ecopia_Est_RDC_%26_Ouest_Ouganda/D%C3%A9roulement>
> Experienced OSM contributors who would be interested in participating
> inthis import will be welcome.
> A similar message regarding this import will also be shared on the OSM
> mailing list of DRC and the HOT mailing list to gather a maximumfeedback.
> Don't hesitate to share your comments, questions, or problemsrelated
> to this import before it begins.
> Best
> Deogratius
> [1] https://wiki.openstreetmap.org/wiki/Humanitarian_OSM_Team[2]
> https://www.hotosm.org/projects/leveraging-ml-generated-building-data-and-motorcycle-mapping-in-the-drc-and-uganda-to-enhance-humanitarian-response/
> *Humanitarian OpenStreetMap Team *Project Manager, Uganda Email:
> kigguddedeogratias at hotosm.org
> <mailto:kigguddedeogratias at hotosm.org>Skype: deogratius kiggudde
> Twitter: @KigguddeDUG Mobile: +256 703 143 225
> http://donate.hotosm.org/
> *Using OpenStreetMap for Humanitarian Response & Economic Development*
> web <http://hotosm.org/> | twitter
> <https://twitter.com/hotosm> | facebook
> <https://www.facebook.com/hotosm> | donate <https://donate.hotosm.org/>
>
> _______________________________________________
> Talk-ug mailing list
> Talk-ug at openstreetmap.org
> https://lists.openstreetmap.org/listinfo/talk-ug
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/talk-ug/attachments/20200709/4132733c/attachment.htm>