Re: [postgis-users] radius of buffer parameter issue at st_buffer function...

2012-01-17 Thread Mike Toews
Are you sure your coordinates are projected? Could you get an example
EWKT from you dataset using:

SELECT ST_AsEWKT(geom)
FROM mytable LIMIT 1;

If you are seeing something like POINT(147.65625 -33.046875), which
has linear units of degrees (not metres), then you need to properly
set the SRID and transform them:

SELECT ST_AsEWKT(ST_Transform(ST_SetSRID(ST_geom, 4326), 3308))
FROM  mytable LIMIT 1;

Note: I'm only guessing 4326 for WGS84, but your data could use a
different datum.

If your geometries are indeed projected, and the linear distances make
sense, make sure your geometries are valid:

SELECT * FROM mytable
WHERE NOT ST_IsValid(geom);

Invalid geometries cause havoc with some operations.

-Mike

On 18 January 2012 12:45, ZHAO Gorton  wrote:
> I am using postgis 1.5 and use the st_buffer function with my spatial 
> queries. I have set the srid to 3308 for my spatial data which the 
> measurement unit is meter, but when I use the st_buffer function and set the 
> radius of buffer in meter. The spatial queries return far more rows than what 
> I expected. The measurement unit of radius of buffer in st_buffer function 
> does not seem to me to be in meter. Instead of using 10 for a radius of 10 
> meters, I have to use a value of 10*1.7453292519943283E-5 instead. What could 
> be the problem with this st_buffer function? I do not mind to use this value 
> but it is not what postgis documented. It would be appreciated if you could 
> help on this.
>
> Regards,
>
> Gorton ZHAO
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[postgis-users] radius of buffer parameter issue at st_buffer function...

2012-01-17 Thread ZHAO Gorton
I am using postgis 1.5 and use the st_buffer function with my spatial queries. 
I have set the srid to 3308 for my spatial data which the measurement unit is 
meter, but when I use the st_buffer function and set the radius of buffer in 
meter. The spatial queries return far more rows than what I expected. The 
measurement unit of radius of buffer in st_buffer function does not seem to me 
to be in meter. Instead of using 10 for a radius of 10 meters, I have to use a 
value of 10*1.7453292519943283E-5 instead. What could be the problem with this 
st_buffer function? I do not mind to use this value but it is not what postgis 
documented. It would be appreciated if you could help on this.

Regards,


Gorton ZHAO
Traffic Management

T 02 9319 9431  F  02 9319 2015

http://www.scats.com.au

http://www.rmservices.nsw.gov.au



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Re: [postgis-users] All object between the coordinates

2012-01-17 Thread Sandro Santilli
On Tue, Jan 17, 2012 at 06:48:50PM +0200, cey...@likya.net wrote:

>I am a newbie on PostGIS. I have a database converted from Netcad Spatial
>Data to PostGIS. My maps seems to work fine but I don't know how to query
>all objects between the following coordinates:
> 
>26.3456 - 27.21546 Eastern Meridians
>36.1254 - 42.87875 Northern Parallels

SELECT the_geom FROM the_table WHERE
 ST_Intersect(
   the_geom,
   ST_MakeEnvelope(26.3456, 36.1254, 27.21546, 42.87875)
 );

Add a SRID parameter to ST_MakeEnvelope to match the SRID
of your column.

Read more in the PostGIS manual.

--strk; 

  ()   Free GIS & Flash consultant/developer
  /\   http://strk.keybit.net/services.html
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Re: [postgis-users] error: undefined symbol: json_tokener_errors in POSTGIS2.0

2012-01-17 Thread Sandro Santilli
On Tue, Jan 17, 2012 at 09:59:45AM -0500, P Mohan wrote:
>
> On Tue, Jan 17, 2012 at 4:15 AM, Sandro Santilli  wrote:
> 
> > On Tue, Jan 17, 2012 at 01:40:51AM -0500, P Mohan wrote:
> >
> > > /usr/lib/postgresql/9.1/lib/postgis-2.0.so: undefined symbol:
> > > json_tokener_errors
> > ...
> > > installed json-c from source from github
> >
> > As root, run:
> >   # ldconfig
>
> i ran the ldconfig (load dynamic configuration) in the same directory as
> json-c make.
> then tried again, still getting the same error.
> 
> is there any thing else that i should check?

Did we solve this on IRC already ?
If not you somebody else had the same problem and solved by 
recompiling libjson-c

--strk;

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[postgis-users] All object between the coordinates

2012-01-17 Thread ceyhun
Hi all,I am a newbie on PostGIS. I have a database converted from Netcad Spatial Data to PostGIS. My maps seems to work fine but I don't know how to query all objects between the following coordinates:26.3456 - 27.21546 Eastern Meridians36.1254 - 42.87875 Northern ParallelsCan anybody help?Many thankstelmessos

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Re: [postgis-users] error: undefined symbol: json_tokener_errors in POSTGIS2.0

2012-01-17 Thread P Mohan
hi Strk,

i ran the ldconfig (load dynamic configuration) in the same directory as
json-c make.
then tried again, still getting the same error.

is there any thing else that i should check?

thanks
pmohan


On Tue, Jan 17, 2012 at 4:15 AM, Sandro Santilli  wrote:

> On Tue, Jan 17, 2012 at 01:40:51AM -0500, P Mohan wrote:
>
> > /usr/lib/postgresql/9.1/lib/postgis-2.0.so: undefined symbol:
> > json_tokener_errors
> ...
> > installed json-c from source from github
>
> As root, run:
>   # ldconfig
>
> --strk;
>
>  ()   Free GIS & Flash consultant/developer
>  /\   http://strk.keybit.net/services.html
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Re: [postgis-users] error: undefined symbol: json_tokener_errors in POSTGIS2.0

2012-01-17 Thread Sandro Santilli
On Tue, Jan 17, 2012 at 01:40:51AM -0500, P Mohan wrote:

> /usr/lib/postgresql/9.1/lib/postgis-2.0.so: undefined symbol:
> json_tokener_errors
...
> installed json-c from source from github

As root, run: 
   # ldconfig

--strk;

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Re: [postgis-users] DXF to Postgis using ogr

2012-01-17 Thread Sandro Santilli
On Mon, Jan 16, 2012 at 10:27:14AM -0800, Bob Pawley wrote:

> QGIS is written in VC++ of which I am not acquainted. 

QGIS is written in C++.

The "V" is not part of the language name, stands for "Visual"
and identifies a proprietary [1] C++ compiler.

 [1] http://en.wikipedia.org/wiki/Proprietary_software

QGIS can be built using any compliant compiler [2]

 [2] http://en.wikipedia.org/wiki/List_of_compilers#C.2B.2B_compilers

QGIS is free software [3]

 [3] http://www.gnu.org/philosophy/free-sw.html

Most QGIS developers use a free software compiler, often GCC [4]

 [4] http://www.gnu.org/software/gcc/

Nobody deserves to write or speak in a language which requires the
use of a black box to interpret or run. 

--strk; 

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