[Mapserver-users] Oracle Spatial extents

[Dimeo, Christopher]

Vladmir-

You may want to exercise caution when re-assigning Coordinate System ID's to
your data.  Your data, presumably, are lat/long coordinates in the WGS84 (ie
SRID=8307).  They might look something like: 45.5000, -90.3000 (45.5 degrees
north, 90.3 degrees West).  This implies certain things about those
coordinates for example that the distance between them is measured on an
arc, units are angular (not linear like feet, meters, etc).

If you just 'call it' something else like UTM Zone 15, or even SRID=8199
(Arc 50, geodetic but on a different datum), you are literally moving your
coordinates.  It's like calling a red car 'blue'.  It still it what it is.

This may work for you in this case, but have caution when/if you need to do
analysis on your data or map it with other datasets.

----------------------------------
B. Christopher Dimeo
Transportation Planning Analyst
Bureau of Planning
Maine Department of Transportation
207.624.3296


Vladimir Guzmán wrote:
>
>Thanks all for your valuable help.
>I solved using SRID=1 (Sinusoidal WGS 84)  instead of SRID=8307 
>(Geodetic WGS 84)
>I don't know the difference, but now I can get (finally) the geometry's 
>extents.
>
>Thanks a lot.
>
>Vladimir Ilich Guzmán R.
>------------------------
>http://www.maintask.com <http://www.maintask.com>  



Vladimir Guzmán wrote:

> Yes, that's what I want.
> But when I try it, Oracle says:
> ORA-13374:  SDO_MBR not supported for geodetic data
> In the documentation says:
> Usage Notes:
> This function is not supported with geodetic data.
>
> What do they mean with 'geodetic data'?
> Data with a SRID?
> The information in the table is stored with SRID 8307 (WGS84). Should 
> I change it in order to make it work?
>
> Thanks a lot for your help.
>
> Vladimir Ilich Guzmán R.
> ------------------------
> http://www.maintask.com <http://www.maintask.com> 
>
>
> Mills, Daniel wrote:
>
>> what you want is
>> SELECT SDO_GEOM.SDO_MBR(c.shape)  FROM cola_markets c;
>>
>> This will give you the mbr (extent) of the shape as a geometry
>> object.  OR
>>
>> CREATE TYPE vertex_set_type as TABLE OF vertex_type;
>>
>> Oracle Spatial defines the object type VERTEX_TYPE as:
>>
>> CREATE TYPE vertex_type AS OBJECT
>>   (x  NUMBER,
>>    y  NUMBER,
>>    z  NUMBER,
>>    w  NUMBER);
>>
>> SELECT c.name, t.X, t.Y
>>   FROM cola_markets c,
>>   TABLE(SDO_UTIL.GETVERTICES(SELECT SDO_GEOM.SDO_MBR(c.shape)  FROM
>> cola_markets c)) t;
>>
>> THIS WILL PUT THE VERTICES INTO A TABLE.
>>
>> Daniel Mills
>> GIS Consultant
>>
>> Tel:    + 44 (0) 1793 865205
>> Fax:    + 44 (0) 1793 865001
>> E-mail:    mills_d at wrcplc.co.uk
>> Website:    www.wrcplc.co.uk <www.wrcplc.co.uk> 
>>
>>
>> Dimeo, Christopher wrote:
>> How about an SDO_AGGR_MBR? (miniumum bounding rectangle)?
>> 
>> ex:  SELECT SDO_AGGR_MBR( yourGeometry ) FROM t.states;
>> 
>> 
>> 
>> ----------------------------------
>> B. Christopher Dimeo
>> Transportation Planning Analyst
>> Bureau of Planning
>> Maine Department of Transportation
>> 207.624.3296
>>
>>-----Original Message-----
>>From: Vladimir Guzmán [mailto:bigfoot at main-task.com
<mailto:bigfoot at main-task.com> ] 
>>Sent: Wednesday, February 18, 2004 12:33 PM
>>To: Dimeo, Christopher; Mapserver-Userlist
>>Subject: Re: [Mapserver-users] Oracle Spatial extents
>>
>>
>>Yes, I tried, but the function returns a polygon very similar to the 
>>original.
>>It does not return a rectangle... :(
>>
>>Thanks,
>>
>>Vladimir Ilich Guzmán R.
>>------------------------
>>http://www.maintask.com <http://www.maintask.com>  
>>
>>
>>
>>Dimeo, Christopher wrote:
>>
>Have you tried returning and SDO_AGGR_CONVEXHULL?  That should give you
>a geometry that is the extent (i.e. convex hull) of any geometries that 
>you give to the method. (SDO_GEOM.SDO_CONVEXHULL).
>
>----------------------------------
>B. Christopher Dimeo
>Transportation Planning Analyst
>Bureau of Planning
>Maine Department of Transportation
>207.624.3296
>
>
>-----Original Message-----
>From: Vladimir Guzmán [mailto:bigfoot at main-task.com
<mailto:bigfoot at main-task.com> ]
>Sent: Wednesday, February 18, 2004 11:59 AM
>To: David Fawcett; Mapserver-Userlist
>Subject: Re: [Mapserver-users] Oracle Spatial extents
>
>
>That's exactly what I need.  The problem is that Oracle Spatial does
>not
>have such a function "extent",
>
>  
>
----------------------------------
B. Christopher Dimeo
Transportation Planning Analyst
Bureau of Planning
Maine Department of Transportation
207.624.3296