[postgis-users] Exporting 3D Shape to PostGIS

[Kevin Neufeld]

Hi Matthew,

Yes.  PostGIS actually supports a 4th dimension, measures, which it 
looks like your ogr utility program populated with '0'. 

You may be interested in these methods to verify this yourself.
ST_zmflag(geometry),
ST_ndims(geometry),
ST_Force_3d(geometry),

ie.
SELECT asewkt(force_3d(the_geom)) from streets_3d where gid=1;

Cheers,
Kevin

Matthew Pulis wrote:
> Hi Kevin and the rest :)
>
> Seems like it did the trick :
>
> select asewkt(the_geom) from streets_3d where gid=1;
>
> "MULTILINESTRING((625304.649659493 214113.544271209 111.1573080888
> 0,625301.199687227 214078.520974251 111.1573080888 0,625299.489760683
> 214056.176602372 111.1573080888 0,625299.289850496 214050.649031119
> 111.1573080888 0))"
>
> As opposed to :
>
> select asewkt(the_geom) from streets where gid=1;
>
> "MULTILINESTRING((625304.649659493 214113.544271209,625301.199687227
> 214078.520974251,625299.489760683 214056.176602372,625299.289850496
> 214050.649031119))"
>
> I can take it that 111.1573080888 is the altitude right? (considered as z
> coordinate) 
>
> Am I right in my supposition?
>
> Thanks a lot for your help :)
>
> Matthew
>
> -----Original Message-----
> From: postgis-users-bounces at postgis.refractions.net
> [mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of Kevin
> Neufeld
> Sent: Friday, February 08, 2008 5:49 PM
> To: PostGIS Users Discussion
> Subject: Re: [postgis-users] Exporting 3D Shape to PostGIS
>
> http://postgis.refractions.net/docs/ch06.html#id2615538
>
> ST_AsText(Geometry) returns the WKT representation according to OGC 
> standards, which does not include 3D values.
>
> Try PostGIS's WKT extension instead: ST_AsEWKT(Geometry)
>
> Cheers,
> Kevin
>
>
> Matthew Pulis wrote:
>   
>> Hi,
>>
>>  
>>
>> I have a 3D Shapefile, which I am trying to export to a PostGIS table.
>>
>>  
>>
>> This is the an extract from the ogrinfo on the shape file :
>>
>>  
>>
>> yancho at Ubuntu:~$ ogrinfo -so streets3d_new_shps/ testogr
>>
>> Geometry: 3D Line String
>>
>> Feature Count: 49746
>>
>> Extent: (610869.384850, 196653.348553) - (676816.248304, 258102.572101)
>>
>> Layer SRS WKT:
>>
>> PROJCS["Lambert Conformal Conic",
>>
>>     GEOGCS["grs80",
>>
>>         DATUM["North_American_Datum_1983",
>>
>>  
>> SPHEROID["Geodetic_Reference_System_1980",6378137,298.257222101]],
>>
>>         PRIMEM["Greenwich",0],
>>
>>         UNIT["degree",0.0174532925199433]],
>>
>>     PROJECTION["Lambert_Conformal_Conic_2SP"],
>>
>>  
>>
>>  
>>
>> I exported this shapefile to PostGIS table and this is the result of this
>> query : 
>>
>>  
>>
>> select astext(the_geom) from streets_3d where gid=1; :
>>
>>  
>>
>> "MULTILINESTRING((625304.649659493 214113.544271209,625301.199687227
>> 214078.520974251,625299.489760683 214056.176602372,625299.289850496
>> 214050.649031119))"
>>
>>  
>>
>> And this is the resulting query from the streets table which is the normal
>> 2D table :
>>
>>  
>>
>> select astext(the_geom) from streets where gid=1; :
>>
>>  
>>
>> "MULTILINESTRING((625304.649659493 214113.544271209,625301.199687227
>> 214078.520974251,625299.489760683 214056.176602372,625299.289850496
>> 214050.649031119))"
>>
>>  
>>
>>  
>>
>> Any idea what I can do so I can start using elevation on this table
>>     
> please? 
>   
>>  
>>
>> Any help will be extremely appreciated
>>
>>  
>>
>> Regards
>>
>>  
>>
>> Matthew
>>
>>  
>>
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>>
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