<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">2016-09-12 10:46 GMT+02:00 Paul Norman <span dir="ltr"><<a href="mailto:penorman@mac.com" target="_blank">penorman@mac.com</a>></span>:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><span class="gmail-">On 9/12/2016 12:59 AM, Björn Harrtell wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
Hi devs,<br>
<br>
I've been working on a new output format function called ST_AsGeobuf these last months. Its purpose is to serialize full query output into the binary format Geobuf containing both geometry and attributes. The implementation is tracked by:<br>
<br>
<a href="https://trac.osgeo.org/postgis/ticket/3599" rel="noreferrer" target="_blank">https://trac.osgeo.org/postgis<wbr>/ticket/3599</a><br>
<a href="https://git.osgeo.org/gogs/postgis/postgis/pulls/4" rel="noreferrer" target="_blank">https://git.osgeo.org/gogs/pos<wbr>tgis/postgis/pulls/4</a> or alternatively <a href="https://github.com/bjornharrtell/postgis/tree/asgeobuf5" rel="noreferrer" target="_blank">https://github.com/bjornharrte<wbr>ll/postgis/tree/asgeobuf5</a><br>
<br>
Geobuf is a binary format specified by Mapbox that can represent similar data and structure as GeoJSON but is more compact and is faster encode and decode. You can read more about Geobuf at <a href="https://github.com/mapbox/geobuf" rel="noreferrer" target="_blank">https://github.com/mapbox/geob<wbr>uf</a> which also serves as the reference implementation to decode at a browser client side.<br>
<br>
Geobuf is in turn based on Googles protobuf standard which I think is similar to a binary XML. My implementation uses the general purpose library protobuf-c to simplify the encoding.<br>
<br>
I hope to be able use this work as a base to also implement support for vector tiles as specified by Mapbox which is also based on protobuf.<br>
<br>
I think the implementation is ready for review and testing. If you have any interest in Geobuf or vector tiles output support I'd appreciate review and/or test result feedback.<br>
<br>
</blockquote>
<br></span>
The MapBox geobuf page states "Note that the encoding schema is not stable yet". Is it premature to put this in PostGIS?<br></blockquote><div><br></div><div>Subjective, I think. I think Mapbox just want to disclaim backwards compatibility in the eventual next major version. Obviously I find it useful right now and do think it can be for others too. If needed, PostGIS could support both the current spec and future ones by parameterization, or drop support if deemed obsolete.</div><div><br></div><div>As far as I know, Mapbox want to evolve the spec so that it can support encoding/decoding as a stream, but there is no telling when/if that work will be completed.</div><div><br></div><div>And as a final observation, if TWKB could be accepted I think Geobuf should be. :)</div><div><br></div><div>/Björn</div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
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