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<p style="margin-top:0;margin-bottom:0">Hello everyone,</p>
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<p style="margin-top:0;margin-bottom:0">Thanks for the suggestions. I've had an offer of hosting (many thanks!) but it's good to know what options are available.</p>
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Roland - thanks for the info on Overpass. Am aware that GeoJSON isn't supposed to be epsg:3857 but I do it that way as it saves a reprojection stage.</p>
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<p style="margin-top:0;margin-bottom:0">Thank,s</p>
<p style="margin-top:0;margin-bottom:0">Nick<br>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Roland Olbricht <roland.olbricht@gmx.de><br>
<b>Sent:</b> 05 February 2019 16:59:48<br>
<b>To:</b> Nick Whitelegg; dev@openstreetmap.org; talk-gb@openstreetmap.org<br>
<b>Subject:</b> Re: [Talk-GB] OSM augmented reality project - affordable hosting recommendations or Overpass?</font>
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<div class="PlainText">Hi,<br>
<br>
> As an alternative, I was wondering how acceptable it would be to use the <br>
> Overpass API to obtain the data? Downloaded data would be cached on the <br>
> device so for a given area, data would only need to be downloaded once.<br>
<br>
I'm fine with such a usage. The fine print is about other issues:<br>
<br>
- Overpass API does support GeoJSON indirectly, but GeoJSON does not <br>
support EPSG:3857, see<br>
<a href="https://tools.ietf.org/html/rfc7946#section-4">https://tools.ietf.org/html/rfc7946#section-4</a><br>
<br>
To get GeoJSON I suggest<br>
<br>
[out:json];<br>
way(south,west,north,east)[highway];<br>
convert link ::=::,::geom=geom();<br>
out geom;<br>
<br>
where (south,west,north,east) is the bounding box.<br>
<br>
As an act of courtesy I suggest to set the "Accept-Encoding: deflate, <br>
gzip" header and use<br>
<br>
[out:json];<br>
way(south,west,north,east)[highway];<br>
if (count(ways) < 20000)<br>
{<br>
convert link ::=::,::geom=geom();<br>
out geom;<br>
}<br>
else<br>
{<br>
make error what="Too many ways in this bounding box";<br>
out;<br>
}<br>
<br>
This compresses the data and bails out if there are more than 20000 ways <br>
in the bounding box, corresponding to between 1 MB and 2 MB of data. <br>
Overpass would happily deliver about 1 GB per user and day, but the <br>
users may have data plans with rather 1 GB per month.<br>
<br>
Thanks,<br>
Roland<br>
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