[postgis-users] Re: Reprojecting data to 4326

[Wacek]

Hello again!

I still can't manage reprojecing this data to SRID:4326. Someone has an idea?

Thanks for all help!

Regards
Wacek

>Hi,
>>>> >
>>>> > I have some data from USA in 'NAD83 Nevada East' fromat (EPSG:32107 -
>>>> > ?). I want to change it to WGS84 (EPSG:4326) using PostGIS. When I use:
>>>> >
>>>> > "select updategeometrysrid('table', 'the_geom', 4326);" resulting values
>>>> > are'nt correct. What am I doing wrong?
>>>> >
>>>> > Thanks in advance for your replies.
>>>> >
>>>> > Best regards
>>>> > Wacek
>>>> >

>>>    
>>>
>>> 
>>> Hi Wacek,
>>> 
>>> calling updategeometrysrid only changes the internal geometries SRID.
>>> It does not reproject them.
>>> You have to explicitly transform the geometries from the source
>>> coordinates system to the target one, using the tranform() function.
>>> 
>>> select transform(the_geom, 4326) from table;
>>> 
>>> You can either create a new table containing the transformed
>>> geometries, or drop SRID constraint on your table, transform the
>>> geometries and re-add the SRID constraint adapted to the new
>>> geometries' SRID

>>  
>>


>>Or:
>>	SELECT updateGeometrySRID('mytable', 'the_geom', 4326);
>>	UPDATE mytable set the_geom =
>>		transform(SetSRID(the_geom, 32107), 4326);

>>--strk;

>----------------------------------

>Hi, again.

> This works but values after reprojection aren't quite correct (every point has the same coordinates). I have checked reprojecting my own points between these two SRIDs and it 
> is correct. I am wondering if the source data SRID is really 32107 ('NAD83 Nevada East'). Vendor does not provide such information. To check this I use UDIG ('User-friendly 
> Desktop Internet GIS') and his layer information feature. After adding a layer from file the visualisation is OK, but after exporting it to DB and trying to visualize it from 
> there no features are rendered. That's why I am asking about reprojecting this data to SRID:4326. I am using source file http://gisgate.co.clark.nv.us/gismo/downloads/scl_l.zip
> containing streets in Clark County in USA. How can I check what SRID is my source data? Maybe someone can try reprojecting source data I have mentioned to 4326 and tell me 
> about the results. 



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