Path: csiph.com!fu-berlin.de!uni-berlin.de!news.dfncis.de!not-for-mail From: =?UTF-8?Q?Hans-Bernhard_Br=c3=b6ker?= Newsgroups: comp.graphics.apps.gnuplot Subject: Re: Substract value from contour line to surface Date: Tue, 18 Sep 2018 20:11:20 +0200 Lines: 22 Message-ID: References: <452156f4-823d-4c96-822e-0ef8d56b0d81@googlegroups.com> <1b1b4ef8-c458-426a-872b-cba3db812414@googlegroups.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-Trace: news.dfncis.de FmiypDbTd3WYGpgF5JiJwQm+Xbn23+kTNlfs5uaTGlC6ye66kd9eZTq5mZ Cancel-Lock: sha1:kXeskKLcgxf6I6Ve/7QuX8GqPpM= User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.0 In-Reply-To: <1b1b4ef8-c458-426a-872b-cba3db812414@googlegroups.com> Content-Language: en-US Xref: csiph.com comp.graphics.apps.gnuplot:4044 Am 18.09.2018 um 07:08 schrieb laterite@laposte.net: > Le lundi 17 septembre 2018 22:25:51 UTC+2, Hans-Bernhard Bröker a écrit : >> Am 17.09.2018 um 17:17 schrieb laterite@laposte.net: >>> Now, I would like to plot the surface of the function G(x,y0)-G(x0,y0). >> How isn't that the exact same surface as G(x,y) itself? You've just >> renamed the second independent variable and subtracted a constant zero! > > > Sorry, my bad, I made a mistake in my explanation : > > I have an analytical 2D function G(x,y) and a .dat file giving me a subset of x0,y0 points solution of the equation dG/dx|_y=0 in a .dat file. > > And no I want to plot G(x,y0)-G(x0,y0) > One key problem is that that isn't actually a surface. It's a set of curves over x; one for each point (x0,y0) from your data set. In total, it's more like a volumetric function f(x,x0,y0), sampled in a somewhat strange way.