Re: What is the fastest way to threshold data?

*To*: mathgroup at smc.vnet.net*Subject*: [mg85927] Re: [mg85898] What is the fastest way to threshold data?*From*: Sseziwa Mukasa <mukasa at jeol.com>*Date*: Thu, 28 Feb 2008 02:43:52 -0500 (EST)*References*: <200802270924.EAA16019@smc.vnet.net>

On Feb 27, 2008, at 4:24 AM, Kevin J. McCann wrote: > I have some 3d data {{x1,y1,z1},{x2,y2,z2},...} and I would like to > set > the z-values to zero if they fall below zero. More generally, I would > like to set z to a threshold value if it is at or below a threshold. > This seems as though it should be an easy enough thing to do, but the > only way I have figured out is to parse out the z-vector, do > > mask=((#<thresh&) /@ zdata)/.True->0/.False->1; > > then > zvector = zvector*mask; > > and rebuild the {x,y,z} data. I would apply a function to each point: If[#3<=thresh,{#1,#2,thresh},{##}]&@@@data Regards, Ssezi

**References**:**What is the fastest way to threshold data?***From:*"Kevin J. McCann" <Kevin.McCann@umbc.edu>