How to make a projection on a 2d histogram and save that projection into a 
vector file.

in paw++

Given a 2d histogram, example id = 408, with yaxis = theta and xaxis = energy.
Make a cut on yaxis for 10.<theta<20. deg. and project onto x axis.

hi/cr/banx 408 10. 20.   (hi/cr/banx id ymin yhi), make a band in y
hi/proj 408  (hi/proj id) One can make multiple cuts on the y axis. This
                          command fills all the projections.
hi/pl 408.banx.1 (hi/pl id.banx.no) plots the selected cut
vec/cr piproj(200) r  (hi/cr vname(size) r) real array of vectors
hi/get_vect/contents 408.banx.1 piproj  (hi/get_vect/contents id vname)
                                        stores the histogram id into vector.
vec/wr piproj piproj.dat  (vec/wr vname filename ) write the vector to a file.


See paw manual or paw++ help in dialog box.