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On Fri, 2007-06-01 at 12:26 -0400, Case.Jon wrote: > Dear Gembud, > > Does anyone know of a way to calculate the standard deviation of a specific > grid using GDLIST? > There is a function to give you the average of a scalar grid over the GAREA, > but I don't see a way to specify a GFUNC that can calculate the standard > deviation. > > Actually, the only missing link I need is to find the number of non-missing > grid points in the array. I haven't identified such a utility though. Jon, You can determine the number of non-missing grid points in your sub area using a function like: GDPFUN = ysum(xsum(bool(S))) The bool(S) function will provide a 1/0 output with 1's at existing points, so the column sumation of the individual row sums will produce a grid of the number of non-missing points at all points. You could further assign the value to just the non-missing point locations (but not needed here) with: GDPFUN = mask(ysum(xsum(bool(S))),S) The standard deviation of the grid area could be done in GDPLOT2 similar to: GDPFUN = ysum(xsum(bool(tmpc)))//n!mul(savs(tmpc),n)//sm!mul(savs(expi(tmpc,2)),n)//ss!sqrt(quo(sub(ss,quo(mul(sm,sm),n)),sub(n,1)) (or the individual terms above can be computed in GDDIAG to output with GDLIST). Steve Chiswell Unidata User Support > > Also, I've looked at the GDSTAT program, but that give you statistics at each > individual grid point over a range of times, not stats for a while grid. > > Your feedback is most welcome! > Jonathan > > ......................................................................The > information contained in this email message is intended only for the use of > the individuals to whom it isaddressed and may contain information that is > privileged and sensitive. If the reader of this message is notthe intended > recipient, you are hereby notified that any dissemination, distribution or > copying of thiscommunication is strictly prohibited. If you have received > this communication in error, please notify thesender immediately by email at > the above referenced address. Thank you. > > =============================================================================== > To unsubscribe gembud, visit: > http://www.unidata.ucar.edu/mailing-list-delete-form.html > =============================================================================== -- Steve Chiswell <address@hidden> Unidata