[OSM-talk] Mali

Pierre Béland pierzenh at yahoo.fr
Sun Jun 30 20:05:49 UTC 2019

John some answers about your concerns
We have our own difficulties in countries like Canada to recruit contributors. Not surpsingly, for  African communities with more difficult economic conditions, they have poor, unstable internet access and less time to contribute.  
Problems are multiple in countries like Mali. It is hard to train and maintain local communities. Following the school and health faicilities imports in 2014, the Mali community has tried to fix bad imports. But has you see there are still problems. The government cannot provide detailed data and the community organize various trips to collect more precise data. 

If the international community could work with the local community and not only organize mapathons discionnected from these communities with too often newbies and problems never corrected. Projects disconnected from the african communities add burden, inconsistent map, Spaghetti has one contributor reported.  

How collectively can we corret that ? We need our partners that organize mapathons to revise their policies to bring in Quality.  Also, it would be interesting that software editors could catch more rapidly duplicates to correct them quickly.

- About Overlapping and duplicate buildings - Tools like Osmose report these. Looking for Mali, it seems that it has been cleaned.

- Large Areas tagged as buildingYou can use this query in JOSM (Overpass Query Panel). If you cover a large zone in one query, your query might be rejected.  In this example, it will query building polygons that have a perimeter longer then 1,000 meters. Only a few were reported in Mali.

[out:xml][timeout:60];way[building](if: length()>1000.0)({{bbox}}); out meta;>; out meta;


    Le dimanche 30 juin 2019 13 h 18 min 55 s UTC−4, john whelan <jwhelan0112 at gmail.com> a écrit :  
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  I think the concerns are more to do with how do we clean it up.

The first major concern is  "Working for a mapping project with Apple."  the concern here is paid mappers and the quality of their work.
The second is there are a fair number of imports of varying quality.  Most schools I suspect are fairly accurate but it would be nice to tie the node to a building or an area.  Some hospitals are very definitely wrong the node is in the middle of nowhere and yes I have checked different imagery.  This really needs local knowledge to sort out.

Much of it is HOT, highways that are mapped to the edge of the task manager tile.  So one highway section gets mapped as track, another as unclassified, another as path, another as tertiary as different mappers put heir own interpretation of what the tag should be.
If some nice person could come up with an overpass that picked out large buildings in Africa that should pick out the villages tagged as buildings.
For paid mappers I think we need a code of conduct.
I think there is sufficient infrastructure in Africa three days for local mappers.  Smartphones are becoming more common and so is an Internet connection albeit driven by social media.
Can we build on this?  Schools need to communicate with parents and other schools.  This sort of implies a postal service which in turn implies names on streets and house numbers.
My impression is there would be an economic advantage, larger cities already have street names.  Could someone do a PhD in the subject which might well mean a bit more government.  My personal view is some things are best done by governments.  Highways for example.
By the way some mappers seem to be non HOT so if we can pick them out and support them a percentage may well be local.
Cheerio John
On Sun, 30 Jun 2019 at 11:24, Andrew Hain <andrewhainosm at hotmail.co.uk> wrote:

Is there any sign of mappers being part of an organised activity or of someone having encouraged them to contribute?
From: John Whelan <jwhelan0112 at gmail.com>
Sent: 29 June 2019 23:49
To: talk at openstreetmap.org
Cc: Pierre Béland via HOT
Subject: [OSM-talk] Mali I've been going over Mali adding in missing villages and hamlets working in the southern and eastern part of Mali and cleaning up as I go.  Adding nodes to highways that cross but have no nodes, adding tags to untagged ways etc.  I even try to make sure each village has one highway at least leading to it. 

However as I work west I'm coming across areas that have lots of buildings and lots of errors.  I've zapped more than a few hundred duplicate buildings.  I confess I have not put a comment on every changeset especially when the mapper has less than 30 edits.  I'm seeing three buildings mapped on top of each other by the same mapper.  One is untagged and its not just once.  Interestingly some of the changesets are tagged "untangling the spaghetti" and I have sympathy with that mapper.

In particular I'm seeing whole villages marked as a single building=yes, villages with highways that don't meet in the middle.  Villages connected by tracks which doesn't match up with the African Highway wiki page.

Most errors are mapped by mappers with not that much experience.  The buildings in some ways are a nuisance as they both seem to be mapped from different imagery so often have been mapped crossing highways etc but the other problem is they fill the map so much so other features are difficult to spot like highways that don't quite meet.

Are there any local Mali mappers around to chat with to see if we can get something organised?  In particular we need the highway classification sorting out.  The African highway wiki is fine as far as it goes but something connecting a village to a highway comes out as unclassified especially if there are square roofs in the village.  In order to differentiate the highways that these connect to that connect a number of villages probably should be tertiary and the ones that connect towns and major villages probably something else. 

However I'd be much more comfortable with some local mappers making these calls.

I'm not sure quite what to do.  It needs a more organized approach.  An Apple mapper has been in demoting highway=tertiary to unclassified and yes we did have a conversation however I'm fairly certain they are working remotely from imagery.


Thanks John

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