Hi Mark, I would suspect that it's because of an integer->floating point conversion. If I remember right Shape is an integer based format, and DXF is floating point based. When you convert a tiny amount of error creeps in. It's one of those computer things you can't really do anything about.
There's more on fmepedia - http://tinyurl.com/l543o A quote I found says... "Floating point is by its nature inexact. It is probably best if you imagined that after every floating point operation, a little demon came in and added or subtracted a tiny number to fuzz the low order bits of your result." I think in this case I'd recommend you use a CoordinateRounder transformer which will give you the correct values. As far as I can tell, not being a mathematician, the error is always so small that it's less than the precision you're likely to be using (ie you'd only have a problem if you're working to about 8 decimal places of precision). Hope this helps, 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], "mrmcclurg" <[EMAIL PROTECTED]> wrote: > > Hey everyone, > > I've got a Polyline-z shapefile with contours, which also have an > attribute with the elevation stated in it. > > I need to convert these files to DXF format, but keep the appropriate z- > value. When I tried to do a straight conversion, the z values got > messed up somehow. 624 would become 623.999999967, and when read into > AutoCAD it would produce 2 623 values, instead of a 623, 624, and 625 > value as it should have done. > > Does anyone know why this is happening? > > Thanks! > > Mark > 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. Safe Software has also made slides available that outline enhancements planned for FME 2007. The slides are from the "Road Ahead" presentation given on Day 2 of the FME Worldwide Users Conference. To view these slides, visit www.safe.com/2006uc. 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/
