<html>
<head>
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
<div class="moz-cite-prefix">On 16/03/2017 21:46, Kate Chapman
wrote:<br>
</div>
<blockquote
cite="mid:CAGn7mOoM9=E5eqeg9c_Fk8rqzFDWCG+ThpmkMBugM5_4VOYn3Q@mail.gmail.com"
type="cite">
<div dir="ltr">1. We can't demand more of Facebook than others
doing imports. When a government releases data under an open
license we don't demand to see the imagery they used to make it.
I purchase the same imagery Facebook does for my job and our
license also ensures that we have the rights to release the
derived vectors under the license we choose. I think this is
sufficient.
<div style="font-size:12.8px"><br>
</div>
</div>
</blockquote>
<br>
Indeed, but it's worth bearing in mind a couple of points:<br>
<br>
1) One is that unless people can compare the source DG imagery with
the the derived roads, it's not possible to judge the process. The
first time that Facebook tried something like this in Egypt nad
Thailand there were a very large number of false positives - many
straight edges with a contrast change in the image (e.g. the edges
of drainage channels in Egypt) were detected as "roads", and even
with real roads there were many connectivity issues. It may well be
that the method by which roads are now detected is much improved
(but it looks like image 3 may show some of the same connectivity
detection problems as before), but without access to the DG imagery
used, no-one can tell.<br>
<br>
2) The discussion on the Thai forum has suggested that it'd be
useful for OSM mappers to access the DG imagery for mapping purposes
other than road derivation (see e.g.
<a class="moz-txt-link-freetext" href="https://forum.openstreetmap.org/viewtopic.php?pid=632472#p632472">https://forum.openstreetmap.org/viewtopic.php?pid=632472#p632472</a> and
<a class="moz-txt-link-freetext" href="https://forum.openstreetmap.org/viewtopic.php?pid=634119#p634119">https://forum.openstreetmap.org/viewtopic.php?pid=634119#p634119</a> ).<br>
<br>
Obviously there may be commercial hurdles to climb in order to do
either of these, but it'd be difficult to comment on the accuracy of
the the import without at least (1). However in case people are
unaware DG have already responded in the forum thread
<a class="moz-txt-link-freetext" href="https://forum.openstreetmap.org/viewtopic.php?pid=634735#p634735">https://forum.openstreetmap.org/viewtopic.php?pid=634735#p634735</a> and
said "we are looking at options to publish", so this may be in hand.<br>
<br>
Best Regards,<br>
<br>
Andy<br>
<br>
</body>
</html>