Hi Roland, I can't think of how to do this off-hand, but it did occur to me that if you have the Scaler and Offsetter working you could set it all up as a Custom Format. I'm not totally sure how that works with multiple layers, but I think there's a good chance it would apply it to all (or at worst you could define all your layers in the custom format, which would be a pain, but a one-off job).
Hope this is of use, Mark --- In [email protected], "Roland Martin" <[EMAIL PROTECTED]> wrote: > > Hi, > > I've got a load of data that needs converting to a local grid that's based > on British National Grid. Up to now I've been doing it in a custom > transformer using a scaler and offsetter, but it would be quite handy if I > could set it up as a custom co-ordinate system, as some of the datasets have > large numbers of layers. Unfortunately the maths is a bit beyond me thus > far, so I was wondering if anyone could help. > > So here's British National Grid, for the uninitiated: > > COORDINATE_SYSTEM_DEF BritishNatGrid \ > DESC_NM "British National Grid (ORD SURV GB) (EPSG #27700)" \ > GROUP "EUROPE" \ > DT_NAME OSGB-7P \ > PROJ TM \ > UNIT METER \ > PARM1 -2.0 \ > ORG_LAT 49.0 \ > SCL_RED 0.9996012717 \ > X_OFF 400000.0 \ > Y_OFF -100000.0 \ > MAP_SCL 1.0 > > ... and the one I'm trying to set up is as follows: > > x = ( ( bngX - 537500 ) / 0.99983344 ) + 27500 > y = ( ( bngX - 185000 ) / 0.99983344 ) + 15000 > > ... so presumably I need to modify the SCL_RED; X_OFF and Y_OFF values. > > Can any local geniuses give me a hand with the numbers here? I've managed to > get it reasonably close, but it's a couple of metres off. > > Thanks, > Roland. > 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/
