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Hi Severin and all others,<br>
<br>
Although I practically stopped working on OSM in CAR, I am still
following the list and read your Wiki-page-style how-to with
interest (reading it I realised I didnt make any of the errors you
mentioned which is nice :) ). I hope to be able to contribute more
in the coming months. Its nice to see so many people emergency-map
for OSM (Yolanda etc), and I hope some will start to work on other
areas as well which are hit badly by crises of a not-so-obvious
nature.<br>
<br>
Regards, <br>
Simeon<br>
<br>
<div class="moz-cite-prefix">Am 14.01.2014 19:24, schrieb Severin
MENARD:<br>
</div>
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cite="mid:CA+y5pB+ge23utJNpQyi_L0zJ_HLhEUXhUo5wPDsHzg+mriASVg@mail.gmail.com"
type="cite">
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<div>Hi Nick,</div>
<div><br>
</div>
<div>Thank you for your email. My answers inline.</div>
<div> </div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">Date:
Sun, 12 Jan 2014 13:48:00 +0000<br>
From: Nick Allen <<a moz-do-not-send="true"
href="mailto:nick.allen.54@gmail.com" target="_blank">nick.allen.54@gmail.com</a>><br>
To: <a moz-do-not-send="true"
href="mailto:HOT@openstreetmap.org" target="_blank">HOT@openstreetmap.org</a><br>
Subject: [HOT] Validation queries<br>
Message-ID: <<a moz-do-not-send="true"
href="mailto:52D29D10.6010009@gmail.com" target="_blank">52D29D10.6010009@gmail.com</a>><br>
Content-Type: text/plain; charset="iso-8859-1";
Format="flowed"<br>
<br>
Hi,<br>
<br>
Would you like me to join in with the validation process?
I am<br>
experienced in mapping OSM, but am fairly new to regularly
mapping HOT<br>
projects.<br>
</blockquote>
<div>Would be great! Thanks for the proposition! Indeed you
have contributed a lot in OSM. Mapping HOT projects is not
very complicated, as you saw with the <a
moz-do-not-send="true"
href="https://wiki.openstreetmap.org/wiki/Highway_Tag_Africa"
target="_blank">Highway_Tag_Africa</a>, it is less
detailed then in developed countries, at least regarding
remote mapping. Maybe the difficulty is when you do not
know how those contexts look like. A goo way to compensate
this is to look for videos posted on Youtube (examples <a
moz-do-not-send="true"
href="http://www.youtube.com/results?search_query=bangui&sm=3"
target="_blank">here</a>), especially the ones taken
along road or streets. This is how you figure out if
properties enclosures are walls, fences or hedges, what is
often a cultural feature. Ah, just saw you mapped some
wall enclosures (eg <a moz-do-not-send="true"
href="http://www.openstreetmap.org/node/27564988#map=19/4.41952/18.51870">here</a>).
They actually are buildings (houses) under construction.
It is frequent in developing countries that such works
last a long time or even be abandoned. </div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><br>
I'm responsible for some of the mapping in<br>
<a moz-do-not-send="true"
href="http://tasks.hotosm.org/job/72" target="_blank">http://tasks.hotosm.org/job/72</a>,
as well as trying to change some of the<br>
more obvious 'highway=track to highway=residential or
unclassified etc..<br>
or it may be easier to check what I've done using my OSM
profile<br>
<a moz-do-not-send="true"
href="http://www.openstreetmap.org/user/Tallguy/history#map=13/4.4168/18.4936&layers=N"
target="_blank">http://www.openstreetmap.org/user/Tallguy/history#map=13/4.4168/18.4936&layers=N</a><br>
<br>
How much validation is actually needed / done? Is it a
proportion of the<br>
whole task, or just until you are confident that, all
things considered,<br>
the task is fulfilled? You're never going to get 100% as
some things<br>
boil down to opinion about what the images actually are
of, but the vast<br>
proportion is pretty obvious.<br>
</blockquote>
<div>This is something that still needs to be settled and
documented. I would say a validation is about both
identifying mistakes/mapping lacks and
standarzation/consolidation and has 2 or three steps,
related to scale:</div>
<div>1. At neighborhood scale, check notably if:</div>
<div>
<ul>
<li>buildings are missing. Sometimes it happens and if
actually it represents a consequent number of building
over a TM task, it can be invalidated</li>
<li>buildings are correctly traced. Hopefully it is not
frequent, but sometimes mappers made really coarse
outlines that do not respect either the buildings
proportions or angle. More frequent are mappers that
do not know how to square the buildings. In this case,
after having checked what is their preferred editor, I
generally send a message to their OSM message box to
give them the tip to do it</li>
<li>highway tags are correct. This is what you
described. Some mappers put tracks wherever it is not
a main road considering it is not paved, but this is
not a meaningful criteria in these developing
countries considering 99% of roads are unpaved. </li>
<li>road geometry. Some mappers do not put enough
details and other too much (eg a node every 10 or 20 m
even if the road is straight). First case is quickly
corrected with the (magical) Improve Way Accuracy mode
in JOSM; second case requires deleting extra nodes
when they actually make weave a straight road. </li>
<li>start/end of roads. Some mappers are experts of
giant snake roads or loop roads, Requires to pass the
mouse over the streets to see their extent and cut
them where it makes sense. On the contrary, some
streets or roads are sawed without any reason (same
tags for all the sections)</li>
<li>general issues of connections between objects. Some
that should be connected and those that should not.
Requires both Validator and also eye control</li>
</ul>
</div>
<div> 2. at the town or city scale, it is quite related to
the road network and its main highways. Having a larger
view to identify the highways that are not simple
residential roads. They are often larger and frame a
larger area or can be a parallel way to main roads. It is
also important to check where they start and when they
stop, what is often not possible to do when you map with
the Tasking Manager. This is what I tried to do with <a
moz-do-not-send="true"
href="http://www.openstreetmap.org/#map=14/5.9374/15.5879">Bouar</a>;
here are some examples of issues for Bangui:</div>
<div>
<ul>
<li><a moz-do-not-send="true"
href="http://www.openstreetmap.org/node/27564988#map=17/4.38964/18.54186">missing
parts of highway</a>. Looks weird on Mapnik and the
check of the imagery confirms the two sides of the
road separated by a drain are not finished</li>
<li><a moz-do-not-send="true"
href="http://www.openstreetmap.org/node/27564988#map=17/4.38686/18.50796">road
continuity</a>. The situation here seems weird as
well as we expect the 2 unclassified roads to be
connected and not joined by a simple path. The imagery
confirms that the southern highway looks the same, and
should be tagged the same, whatever the tag. The
example is actually good as <a moz-do-not-send="true"
href="http://www.openstreetmap.org/node/27564988#map=17/4.37643/18.50931">farther
south</a>, it changes for tertiary. No reason for
this, says the imagery. It should be cut when it
becomes a straight road, though</li>
<li><a moz-do-not-send="true"
href="http://www.openstreetmap.org/node/27564988#map=15/4.4070/18.5068">isolated
upper-level road sections</a>. Drivable highways
cannot be isolated and connected to the drivable road
network by paths, they must be connected to it</li>
<li><a moz-do-not-send="true"
href="http://www.openstreetmap.org/#map=15/4.4333/18.5314">tagging
coherence</a>. in this example, the primary and
tertiary road are connected by a unclassified road.
Same thing between the two tertiary roads. After
having checked the imagery this road would deserve to
be tagged as tertiary. This obvious example apart,
this requires to check the streets width to identify
the main ones that needs not to be tagged as
residential but unclassified or even tertiary.</li>
</ul>
<div>Hope this can help! I had in mind to give some tips
and it became a start for a future wikipage :) Hope
other people will read/discuss/complete this.</div>
<div><br>
</div>
<div>Sincerely,<br>
</div>
</div>
<div><br>
</div>
<div><br>
</div>
<div>Severin</div>
<div><br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">Any
constructive feedback from experienced HOT mappers is
welcomed.<br>
<br>
<br>
Regards<br>
<br>
Nick<br>
</blockquote>
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<pre wrap="">_______________________________________________
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