[postgis-users] KML Export

[Eduin Carrillo]

Hi Stefan.

Geometry Outputs[1] functions (ST_As*) allow you output geometric
fields as geometric representations. ST_AsKML do not return full KML
documents, but descendant objects of <Geometry>[2] abstract object in
KML.

This is a best expression of your query:
SELECT  ST_AsKML(the_geom)
FROM my_spatial_table
WHERE ....

[1] http://www.postgis.org/documentation/manual-1.4/ch07.html#Geometry_Outputs
[2] http://code.google.com/intl/en/apis/kml/documentation/kmlreference.html#geometry

Eduin Yesid Carrillo Vega
Ingeniero Civil, Esp. Sistemas de Información Geográfica
Grupo IDE & GIG
Centro de Investigación y Desarrollo en Información Geográfica
Instituto Geográfico Agustín Codazzi - IGAC
Cr 30 48-51
Tel +57 1 3694000  ext 4305
Bogotá D.C., Colombia



On Wed, Jul 15, 2009 at 2:44 AM, Stefan
Schwarzer<stefan.schwarzer at grid.unep.ch> wrote:
> Ah, thanks a lot! That sounds great!
> However, when inserting the function and executing this:
> SELECT askml('my_title', 'description', collect(the_geom)) FROM (SELECT
> c.the_geom FROM countries_view AS c) AS foo
> I get this error:
>
> 	ERROR:  geometry_to_kml: 'GeometryCollection' geometry type not supported
> by Google Earth
> 	CONTEXT:  SQL function "askml" statement 1
> 	PL/pgSQL function "askml" line 21 at assignment
>
> If I understand it correctly from this conversation, I'd need the latest
> version of Postgis to solve that issue, right?
> Thanks for your valuable help,
> Stefan
> On Jul 14, 2009, at 5:50 PM, Kevin Neufeld wrote:
>
> As you've seen, there is the ST_AsKML command
> (http://postgis.refractions.net/documentation/manual-svn/ST_AsKML.html) that
> will convert a single geometry to KML.
>
> All you need to do is add some xml tags before the export geometry tag and
> again after, closing the document.
>
> Here's an example of a simple wrapper that does this inside the database,
> though you'd probably want to do this in PHP:
> http://lists.refractions.net/pipermail/postgis-users/attachments/20070914/7a02d424/askml.sql
>
> Example use case:
> SELECT askml('my_title', 'description', collect(the_geom))
> FROM my_spatial_table
> WHERE ....
>
> yields something like:
> <?xml version='1.0' encoding='UTF-8'?>
> <kml xmlns='http://earth.google.com/kml/2.1'>
> <Document>
> <name>'my_title'</name>
> <description>'description'</description>
>
> <Style id='defaultStyle'>
>  <LineStyle>
>    <color>ff00ff00</color>
>    <width>1</width>
>  </LineStyle>
>  <PolyStyle>
>    <color>5f00ff00</color>
>  </PolyStyle>
> </Style>
>
> <Placemark>
>  <styleUrl>#defaultStyle</styleUrl>
>  <MultiGeometry>
>    <Point>
>      <coordinates>-122.319,47.164</coordinates>
>    </Point>
>    <Point>
>      <coordinates>-122.272,47.067</coordinates>
>    </Point>
>  </MultiGeometry>
> </Placemark>
>
> </Document>
> </kml>
>
> Cheers,
> Kevin
>
>
>
> Stefan Schwarzer wrote:
>
> Hi there,
>
> I made a tour on Google to look around if there exist some KML export tool.
> I've seen the Set_AsKML command; I've seen this
> <http://postgis.refractions.net/pipermail/postgis-users/2007-September/017070.html>
> dicussion; and have found that someone wrote a script
> <http://postgis3d.blogspot.com/2007/12/googleearth-export.html> for postgis;
> and a phyton script
> <http://dev.riverchange.org/google_earth/genshi_template.kml>. But it seems
> that there is no easy-way-to-go export/wrapper script, enabling for example
> the execution of pgsql2kml...
>
> Or can someone give be a hint how to develop a KML export for a PHP based
> Data Portal?
>
> Thanks for any help,
>
> Stef
>
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