[Georuby-devel] Srid auto detection, manual models configuration.

ValiSystem vali.system at free.fr
Tue Mar 20 07:12:24 EDT 2007


On 19 mars 07, at 19:50, ValiSystem wrote:

>
> Hello,
>
> I've beeing testing GeoRuby all this afternoon, and i've some  
> question/suggestions :
>
> 1. Is there a way to define manually the geometry colomun using the  
> table model ?
> i think about something like that :
>
> class Numvoiri < ActiveRecord::Base
>   set_table_name "numvoiri"
>   set_primary_key "numvoiri_id"
>   set_srid 4326
>   set_geometry_columns ["geom"]
>   belongs_to :text,
>              :class_name => "NumvoiriText",
>              :foreign_key => "text_id"
> end
>
> to define column and override auto detection. I didn't manage to  
> find something like that in docs, but i guess it's just missing. Or  
> if needs to be coded, it could be nice to do it :)
>
> 2. As it's wrote in the docs, Postgis refuses to use operators  
> between geometries with different srids. But this could be  
> autodetected easily :
>
> select srid from geometry_columns where
> 	f_table_catalog = '<the_catalog>' and
> 	f_table_schema = '<the_schema>' and
> 	f_table_name = '<the_table_name>' and
> 	f_geometry_column = '<the_geometry_column>';
>
> Since tuples from geometry_columns are primary keys one attributes  
> used in this where clause, you can safely assume that it will  
> return a single element. Also, i would not, by default, define  
> f_table_catalog and f_table_schema, and reduce query to always  
> known attributes :
>
> select srid from geometry_columns where
> 	f_table_name = '<the_table_name>' and
> 	f_geometry_column = '<the_geometry_column>';
>
> and provide a mechanism to user to make them able to define the  
> schema and catalog, and leave them the responsability to check that  
> (but that needs to warn if several tuples are returned).
>
> I may patch post_gis_adapter.rb  myself if you're interested, but i  
> don't have a deep knowledge of rails internals.
>
> Thanks for the good work.
>
>
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okay i read more things about georuby internals, and it seems that  
my  2. remarks are totally pointless :)

but i'm still interested for suggestions to setup a manuel model  
definition.




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