Width of MBR for each polygon

Question

I need to create a view that is being used in a jsp. It needs to select from a series objects : the centrex, centrey and a "zoom width" in meters for each object. The centre x and y is not a problem as it is in the underlying tables. However i need to generate the zoom width in the view. The zoom width being the width of the polygon , therefore the view/jsp shows the entire polygon on the web page. However the jsp will only display the zoom width as a number field therefore i do not know if i generate the view using a sdo_geom function or a nother function. Is it possible to use several functions (and if so what would they be) e.g sdo_mbr or sdo_adrea to achieve this zoom width as a number field (in meters) or should i be going about it another way.

Answer 1

you could use the SDO_GEOM.SDO_MAX_MBR_ORDINATE and
SDO_GEOM.SDO_MIN_MBR_ORDINATE function for this.
(http://download.oracle.com/docs/html/B14255_01/sdo_objgeom.htm#i866249)
width: delta x of the MBR:
select SDO_GEOM.SDO_MAX_MBR_ORDINATE(geometry, 1) - SDO_GEOM.SDO_MIN_MBR_ORDINATE(geometry, 1)
from table_name
height: delta y of the MBR:
select SDO_GEOM.SDO_MAX_MBR_ORDINATE(geometry, 2) - SDO_GEOM.SDO_MIN_MBR_ORDINATE(geometry, 2)
from table_name
Maybe you need the max of the delta's as your width in order to have the geometry completly in your map area when zoomed to it, but this can be dependant from your application
select ID, MAX(delta)
from
select ID, SDO_GEOM.SDO_MAX_MBR_ORDINATE(geometry, 1) - SDO_GEOM.SDO_MIN_MBR_ORDINATE(geometry, 1) as delta
from table_name
union
select ID, SDO_GEOM.SDO_MAX_MBR_ORDINATE(geometry, 2) - SDO_GEOM.SDO_MIN_MBR_ORDINATE(geometry, 2) as delta
from table_name
group by id
Luc