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List: postgis-users
Subject: Re: [postgis-users] Postgis out-db raster
From: Darafei_"Komяpa"_Praliaskouski <me () komzpa ! net>
Date: 2021-11-26 8:11:01
Message-ID: CAC8Q8tLAGKEqZ8+PTCXeHeR5irLngdZTYm+ncnBKQz79WGzePw () mail ! gmail ! com
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Hi,
outdb rasters are not part of supported Postgres machinery and are really a
pretty illegal hack.
If you keep your inputs out of DB, and your outputs out of DB, you may
really want to move the processing part out of DB too and use GDAL to do
the calculations.
The postgres way to handle that would be to redesign and reimplement the
outdb raster machinery as foreign data wrapper, similar to ogr_fdw. I am
not aware of such initiatives.
On Fri, Nov 26, 2021 at 10:49 AM paul wither <paul.wither@hotmail.com>
wrote:
> Hi there,
>
> I was wondering if anyone would be able to offer some advice on running a
> raster process in postgis.
>
> The input rasters are stored as out-db, then they run through a couple of
> steps, eg reclass a couple of map algebra steps and finally a result
>
> At each step a new raster is created and I can't quite figure out if ther=
e
> is a way (or best way) to specify that the result is written out to a new
> out-db tiff rather than a new internal table
> currently everything writes to new internal table, but there will be clos=
e
> to a thousand tables eating up a lot of space. I understand the performan=
ce
> impacts, but the process is not that time precious.
> Initially I thought that maybe I had to use AsGDALRaster then reload, but
> then I read about creating empty rasters and adding bands. does anyone ha=
ve
> any suggested approaches (noting I'm no sql pro =F0=9F=99=82)
>
> any hints, tips or examples would be greatly appreciated
>
> cheers
>
> Paul
>
> _______________________________________________
> postgis-users mailing list
> postgis-users@lists.osgeo.org
> https://lists.osgeo.org/mailman/listinfo/postgis-users
>
[Attachment #5 (text/html)]
<div dir="ltr">Hi,<div><br></div><div>outdb rasters are not part of supported \
Postgres machinery and are really a pretty illegal hack.</div><div><br></div><div>If \
you keep your inputs out of DB, and your outputs out of DB, you may really want to \
move the processing part out of DB too and use GDAL to do the \
calculations.</div><div><br></div><div>The postgres way to handle that would be to \
redesign and reimplement the outdb raster machinery as foreign data wrapper, similar \
to ogr_fdw. I am not aware of such initiatives. </div></div><br><div \
class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Nov 26, 2021 at 10:49 \
AM paul wither <<a \
href="mailto:paul.wither@hotmail.com">paul.wither@hotmail.com</a>> \
wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px \
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div dir="ltr">
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
Hi there,</div>
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
<br>
</div>
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
I was wondering if anyone would be able to offer some advice on running a raster \
process in postgis.</div> <div \
style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)"> \
<br> </div>
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
The input rasters are stored as out-db, then they run through a couple of steps, eg \
reclass a couple of map algebra steps and finally a result</div> <div \
style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)"> \
<br> </div>
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
At each step a new raster is created and I can't quite figure out if there is a \
way (or best way) to specify that the result is written out to a new out-db tiff \
rather than a new internal table</div> <div \
style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)"> \
<span style="color:rgb(0,0,0);font-family:Calibri,Helvetica,sans-serif;font-size:12pt">currently \
everything writes to new internal table, but there will be close to a thousand tables \
eating up a lot of space. I understand the performance impacts, but the process is \
not that time precious.</span></div> <div \
style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)"> \
<span style="color:rgb(0,0,0);font-family:Calibri,Helvetica,sans-serif;font-size:12pt">Initially \
I thought that maybe I had to use AsGDALRaster then reload, but then I read about \
creating empty rasters and adding bands. does anyone have any suggested approaches \
(noting I'm no sql pro <span id="gmail-m_2051852242422972348🙂">🙂)</span> \
</span></div> <div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
<span style="color:rgb(0,0,0);font-family:Calibri,Helvetica,sans-serif;font-size:12pt"><br>
</span></div>
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
<span style="color:rgb(0,0,0);font-family:Calibri,Helvetica,sans-serif;font-size:12pt">any \
hints, tips or examples would be greatly appreciated</span></div> <div \
style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)"> \
<span style="color:rgb(0,0,0);font-family:Calibri,Helvetica,sans-serif;font-size:12pt"><br>
</span></div>
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
<span style="color:rgb(0,0,0);font-family:Calibri,Helvetica,sans-serif;font-size:12pt">cheers</span></div>
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
<span style="color:rgb(0,0,0);font-family:Calibri,Helvetica,sans-serif;font-size:12pt"><br>
</span></div>
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
<span style="color:rgb(0,0,0);font-family:Calibri,Helvetica,sans-serif;font-size:12pt">Paul</span></div>
<div style="font-family:Calibri,Helvetica,sans-serif;font-size:12pt;color:rgb(0,0,0)">
<span style="color:rgb(0,0,0);font-family:Calibri,Helvetica,sans-serif;font-size:12pt"> \
</span><br> </div>
</div>
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</blockquote></div>
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