I presume that you are not after the length of a polygon's bounday but the length of a medial line after its construction from a polygon?
Oracle 11gR2 does not have such a capability. It might do in 12c but no one knows what is planned for that release, spatially.
I have been contacted a number of times about implementing a medial axis algorithm for my Spatial Companion 4 Oracle (SC4O) free software. It can be done as this example from wikipedia shows:
But I am not prepared to implement such an algorithm without 1) real data and, 2) some sort of incentive.
As Simon mentioned, there is no native function in Oracle Spatial to generate a centreline for a polygon and I am not aware of any existing implementation that will run in Oracle. There are various implementations in commercial software applications, but I guess I can't list them here.
If you are interested in reading more about generating polygon centrelines, there is an excellent blog series on the Smathermather's blog:
Yes. I was interested in the length of the medial line.
I searched all the oracle functions and your site and after exhaustion I put down this question.
Since it is simple sleeve around gas pipes with constant diameter, I devised a workaround to resolve the current problem. But to determine medial line on complex polygon as mentioned in John's example will require more involvement. I also used Safe Software 'CenterLineReplacer' with success.
It is better we have this as of part of future oracle functions.
Edited by: navaneet on Oct 16, 2012 4:21 PM