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List:       postgis-users
Subject:    Re: [postgis-users] ST_CreateOverview doesn't honor tilesize
From:       Senshi <tassilo.m () gmail ! com>
Date:       2017-08-31 7:34:54
Message-ID: CAEUjgb9Texw3jbyULEXvnwOkmrsyKNKYL-VBXwx-n+kxkjGwFA () mail ! gmail ! com
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Thanks, seems it's a long standing issue that sadly nobody has tackled yet.

It seems ST_CreateOverview has even more issues, such as occasionally
generating empty pixel rows/columns at tile edges.

I uploaded an example of this issue for better understanding:
http://imgur.com/a/izlZX

I really would have loved to use PostGIS as a low level  WMTS server, but
these issues are making it difficult :( .

best regards
Senshi

On Wed, Aug 30, 2017 at 8:45 PM, Mateusz Loskot <mateusz@loskot.net> wrote:

> On 30 August 2017 at 14:52, Senshi <tassilo.m@gmail.com> wrote:
> > Hello,
> >
> >
> > when creating an overview, the tilesize of the original tiles is not
> fully
> > respected.
> >
> > If you have a 2x2 grid of tiles with 256x256 pixels each, and then
> create an
> > overview with a scale of 3,  the resulting single tile will end up as 171
> > pixels wide/tall.
>
> Overview with factor = 3 are 'special'.
>  Have a look at discussion here
> https://trac.osgeo.org/postgis/ticket/1764
>
> Best regards,
> --
> Mateusz Loskot, http://mateusz.loskot.net
> _______________________________________________
> postgis-users mailing list
> postgis-users@lists.osgeo.org
> https://lists.osgeo.org/mailman/listinfo/postgis-users

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<div dir="ltr">Thanks, seems it&#39;s a long standing issue that sadly nobody has \
tackled yet.<div><br></div><div>It seems ST_CreateOverview has even more issues, such \
as occasionally generating empty pixel rows/columns at tile \
edges.<div><br></div><div>I uploaded an example of this issue for better \
understanding:</div><div><a \
href="http://imgur.com/a/izlZX">http://imgur.com/a/izlZX</a><br></div></div><div><br></div><div>I \
really would have loved to use PostGIS as a low level   WMTS server, but these issues \
are making it difficult :( .</div><div><br></div><div>best \
regards</div><div>Senshi</div><div class="gmail_extra"><br><div \
class="gmail_quote">On Wed, Aug 30, 2017 at 8:45 PM, Mateusz Loskot <span \
dir="ltr">&lt;<a href="mailto:mateusz@loskot.net" \
target="_blank">mateusz@loskot.net</a>&gt;</span> wrote:<br><blockquote \
class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc \
solid;padding-left:1ex"><span class="">On 30 August 2017 at 14:52, Senshi &lt;<a \
href="mailto:tassilo.m@gmail.com">tassilo.m@gmail.com</a>&gt; wrote:<br> &gt; \
Hello,<br> &gt;<br>
&gt;<br>
&gt; when creating an overview, the tilesize of the original tiles is not fully<br>
&gt; respected.<br>
&gt;<br>
&gt; If you have a 2x2 grid of tiles with 256x256 pixels each, and then create an<br>
&gt; overview with a scale of 3,   the resulting single tile will end up as 171<br>
&gt; pixels wide/tall.<br>
<br>
</span>Overview with factor = 3 are &#39;special&#39;.<br>
  Have a look at discussion here<br>
<a href="https://trac.osgeo.org/postgis/ticket/1764" rel="noreferrer" \
target="_blank">https://trac.osgeo.org/<wbr>postgis/ticket/1764</a><br> <br>
Best regards,<br>
<span class="HOEnZb"><font color="#888888">--<br>
Mateusz Loskot, <a href="http://mateusz.loskot.net" rel="noreferrer" \
target="_blank">http://mateusz.loskot.net</a><br> \
______________________________<wbr>_________________<br> postgis-users mailing \
list<br> <a href="mailto:postgis-users@lists.osgeo.org">postgis-users@lists.osgeo.org</a><br>
 <a href="https://lists.osgeo.org/mailman/listinfo/postgis-users" rel="noreferrer" \
target="_blank">https://lists.osgeo.org/<wbr>mailman/listinfo/postgis-users</a></font></span></blockquote></div><br></div></div>



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