Hi guys,
Is it possible to create an actual jpeg image using ST_AsJPEG? For example
select ST_AsJPEG(rast) from area_dem \g image.jpg
Joan
You can also use gdal_translate...
Pierre
I ended up binary-editing the result afterwards.
Anyway, first step is declaring a binary cursor,
redirecting output to a file and calling the function.
For the binary editing, I looked at another file with
my expected format to tell where it started (human eye
pattern matching).
Much better, when it works (it wasn't working for me).
--strk;
,------o-.
| __/ | Delivering high quality PostGIS 2.0 !
| / 2.0 | http://strk.keybit.net
`-o------'
Thanks,
Do you see any way to make the file directly readable (without having to edit it)?
Pierre
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Yes, I want to create a jpeg/tiff file. I am new to cursors, how would that
work in a query.
I could find no way with current psql. Something to improve there.
You can of course do it with scripts.
--strk;
,------o-.
| __/ | Delivering high quality PostGIS 2.0 !
| / 2.0 | http://strk.keybit.net
`-o------'
So you might have to write a script connecting to PostgreSQL and writing the file for you. See an example in:
http://www.bostongis.com/blog/index.php?/archives/175-Minima[..]
Pierre
We have this documented in the docs.
http://www.postgis.org/documentation/manual-svn/using_raster[..]
ter_Applications
There is an example for doing it with PHP, .NET, Java, and PLPython
Sorry don't have one for psql only. Haven't tried using psql for outputting
files.
Regina
http://www.postgis.us
The last two solutions result in a black square, which I think is the tile.
But it's a good start. I will have to look more into that.
Regina, I have tried using \g to out put to a file but the file is
corrupted.
I appreciate the help.
Joan
Yah psql doesn't make it easy. I've put in an example of doing it in docs.
Which takes tips from this article:
http://people.planetpostgresql.org/andrew/index.php?/archive[..]
ck-challenge.html
There are other examples in that article but this is the only one that
doesn't require Perl or Unix so is more cross platform.
I think strk has one too though his probably requires perl or some unixy
thing.
Docs I don't think have rebuilt yet, but basic script is this:
SELECT oid, lowrite(lo_open(oid, 131072), png) As num_bytes
FROM
( VALUES (lo_create(0),
ST_AsPNG( (SELECT rast FROM aerials.boston WHERE rid=1) )
) ) As v(oid,png);
-- you'll get an output something like --
oid | num_bytes
---------+-----------
2630819 | 74860
-- next note the oid and do this replacing the c:/test.png to file path
location
-- on your local computer
\lo_export 2630819 'C:/temp/aerial_samp.png'
-- this deletes the file from large object storage on db
SELECT lo_unlink(2630819);
Thanks,
Regina
h < http://www.postgis.us> > ttp://www.postgis.us
_____
Here it is in the docs now:
http://postgis.refractions.net/documentation/manual-svn/usin[..]
l#RasterOutput_PSQL
_____
Curious that the question was never raised for ST_AsKML(geometry)...
ST_AsKML(geometry) would be returning XML so suffers no binary issues.
-bborie
--
Bborie Park
Programmer
Center for Vectorborne Diseases
UC Davis
530-752-8380
bkpark*******
Hi Regina
Citation from there: "Sadly PSQL doesn't have easy to use built-in
functionality for outputting binaries..."
Did anyone show and discuss this issue with postgres specialists?
--Stefan
I don't think there's much to discuss.
I'm sure a patch to psql would be welcome.
--strk;
,------o-.
| __/ | Delivering high quality PostGIS 2.0 !
| / 2.0 | http://strk.keybit.net
`-o------'
Sorry, I did not realize that the solution is straight forward :->
--Stefan
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