Hi Ben, The bad news I have is that I don't think this will ever work this way. The problem is that group-based transformers - of which Clipper is one - aren't suitable for use within a loop. As the help document says...
"You can't use transformers that must process all features before returning a result (for example, a Sorter). These are sometimes referred to as 'blocking transformers.'" The reasoning is that a loop processes one feature at a time, and so it isn't possible to form a group from one feature. In your example, admittedly you are creating the group within the loop, multiplying a single feature. However, I think FME is getting confused because more features exit the loop than enter. I'm thinking you must be using FME2006GB, because 2007 has been tightened up so that the workspace will refuse to run if it finds a blocking transformer inside a loop. As for what you are trying to do, the only thing I can think of is to simulate a loop by placing the custom transformer, say, five times (where 5 is the maximum number of nested holes that you can have). It's not pretty but it would work I think. The Tiler transformer may also be an alternative if you upgrade to FME2007, since that version allows you to use an attribute as the tile width; so calculate (maxX-minX)/2 and use that for the tile width. Alternatively, if you don't really care about the shape of the output and you just want to get rid of the donuts, then Hans van der Maarel created a custom transformer that might help. See... http://www.fmepedia.com/index.php/DonutKiller Hope this helps to explain. Regards, Mark Mark Ireland, Senior Product Specialist Safe Software Inc. Surrey, BC, CANADA [EMAIL PROTECTED] http://www.safe.com Solutions for Spatial Data Translation, Distribution and Access --- In [email protected], "Ben Wiles" <[EMAIL PROTECTED]> wrote: > > Hi all, > > I have a custom transformer that loops over a set of donut areas and > tiles the donut areas to produce regular areas. > > Everything works OK, until some features are about to be passed > through the loop transformer for the first time. > > When the features are passed through the tester transformer directly > before the loop, the following output is logged: > > --snip-- > TileDonuts_TESTER_FAILED Feature Counter 1 11(TeeFactory): Cloned 1 > input feature(s) into 0 output feature(s). > Loop to TileDonuts_INPUT_2 Input Splitter(BranchingFactory): Branched > 1 input feature -- 0 features routed to the target factory, and 0 > features routed to the fallback factory. > --snip-- > > It appears that the loop transformer fails to receive valid features > from the FAILED port on the tester, even though the TESTER_FAILED > reports that it cloned 1 input feature. > > If I attach a visualizer transformer to the TESTER_FAILED port, I can > see the single feature as expected. Somehow, the loop transformer > does not recognise this same feature. > > I have attached an example workspace in the files section of the yahoo > group website. The workspace is called 'tile_donuts.fmw'. This > workspace illustrates the problem. > > It would be awesome if someone can spot the problem. > > Many thanks, > > BenW > For insights into what's up at Safe Software and what's on the development horizon, visit Safe's blog at spatial-etl.blogspot.com. Love FME? Then open your diary to March 6-7, 2008 and write this... "Second Worldwide FME User Conference - Must Attend!" See http://www.safe.com/company/fmeuc2008/index.php for more details. Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/fme/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/fme/join (Yahoo! ID required) <*> To change settings via email: mailto:[EMAIL PROTECTED] mailto:[EMAIL PROTECTED] <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
