Mikael, The item "ProjectionX" in the TH2 context menu makes a projection, but does not draw it. If you have a TBrowser open, you can click on the generated histogram named "hhh_px" if "hhh" is the name of your TH2. Otherwise from the command line, do: hhh->ProjectionX()->Draw(); Rene Brun Mikael Bonnier wrote: > > Hi, I'm new to this list. > > I'm using ROOT 3.05/05 on Linux RH9. > > I have a problem getting ProjectionX and ProjectionY to > work. I have a TCanvas containing a 2D-histogram (TH2F) > that is containing some 200000 events. There are > about 400 by 400 bins and the data is [0,2500] by [0,2500]. > When I right-click and choose ProjectionX and enter d as > option I get a new histogram but it's empty, even though the > 2D-histogram contains a lot of data. As I understand it, > ProjectionX kind of should drop all dots onto the x-axis, > or have I misunderstood something? Anyway, this is what I > want to do. > > Regards, > // Mikael Bonnier > // Webb: http://www.df.lth.se/~mikaelb/ > // E-post: mikaelb@df.lth.se > // ICQ # 114635318 > // Mob/SMS: 0701-40 76 89 > // Tel/Fax: 046-32 32 08 > // Exjobb: 046-222 76 34
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