X-Received: by 2002:a02:6c2:: with SMTP id 185-v6mr22529775jav.62.1537281257889; Tue, 18 Sep 2018 07:34:17 -0700 (PDT) X-Received: by 2002:aca:ec87:: with SMTP id k129-v6mr49524oih.2.1537281257298; Tue, 18 Sep 2018 07:34:17 -0700 (PDT) Path: csiph.com!weretis.net!feeder6.news.weretis.net!feeder.usenetexpress.com!feeder-in1.iad1.usenetexpress.com!border1.nntp.dca1.giganews.com!nntp.giganews.com!x81-v6no77923ita.0!news-out.google.com!c63-v6ni101ith.0!nntp.google.com!x81-v6no77921ita.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.graphics.apps.gnuplot Date: Tue, 18 Sep 2018 07:34:16 -0700 (PDT) In-Reply-To: Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=73.117.121.104; posting-account=yC8mVwkAAADuRBqBIdPVfec50l5EMdYn NNTP-Posting-Host: 73.117.121.104 References: <452156f4-823d-4c96-822e-0ef8d56b0d81@googlegroups.com> <1b1b4ef8-c458-426a-872b-cba3db812414@googlegroups.com> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: <97b7cda5-a9d0-43c8-90db-cfaa918867c6@googlegroups.com> Subject: Re: Substract value from contour line to surface From: Gavin Buxton Injection-Date: Tue, 18 Sep 2018 14:34:17 +0000 Content-Type: text/plain; charset="UTF-8" Lines: 21 Xref: csiph.com comp.graphics.apps.gnuplot:4042 I too am confused, but maybe its because your system is complex. Let me try and see if a simpler system helps. So if you wanted to subtract a function from a plot of data you could do something like this. Here's my data in a temporary file named temp.dat 0 1 1 2 2 4 3 7 4 11 5 16 Now I want to subtract a function f(x) which I define below. f(x) = x and then plot the data, but my y-axis is the data minus the function evaluated at x (in column 1) plot 'temp.dat' u 1:($2 - f($1)) I'm not too sure if this is what you are trying to do or not, but I hope it helps!