Fill area below curve from filecontents in PGFPlots

Question

I would like to shade an area underneath a curve. Although this has received attention in previous posts, such as this, I am instead plotting some data using the filecontents package - so the function is not known.

I have the following MWE to exemplify:

MWE

\documentclass[tikz]{standalone}
\usepackage{pgfplots,mathtools} 
\usepackage{filecontents}       
\usepgfplotslibrary{fillbetween}
\usepackage{amsmath,amssymb,bm}
\pgfplotsset{compat=newest}

\begin{document}

\pgfplotstableread{results.dat}{\Results}

\begin{tikzpicture}[]
    \begin{axis}[width=\columnwidth,
        height=0.618\columnwidth,
        ymode=log,
        xlabel style = {font=\Large, yshift=0.5ex},
        ylabel style = {font=\Large, yshift=-1.1ex},
        xlabel={SNR (\text{dB})},
        ylabel={MSE (\text{rad}$^2$)},
        xmin=-40, xmax=15,  
        axis line style={line width=1pt},
        xticklabel style = {font=\Large,yshift=-0.2ex},
        yticklabel style = {font=\Large,xshift=-0.2ex},
        xtick={-40,-30,-20,-10,0,10},   
        xticklabels={-40,-30,-20,-10,0,10},
    ]   
    \addplot [black, line width=1pt] table [x={x}, y={s}] {\Results};
    \end{axis}
\end{tikzpicture}

\end{document}

Although this won't run since the results.dat file is required, it illustrates that I would like to shade the area beneath the \addplot.

The results.dat file looks a bit like this:

x   s
-40.    0.22629270534185614
-39.99  0.22626343334210333
-39.98  0.22623410146157807
-39.97  0.22620470959434436
-39.96  0.22617525763435084
-39.95  0.22614574547543148
-39.94  0.2261161730113055
-39.93  0.22608654013557797
-39.92  0.22605684674173948
-39.91  0.22602709272316673
-39.9   0.22599727797312288
-39.89  0.22596740238475727
-39.88  0.2259374658511061
-39.87  0.22590746826509253
-39.86  0.22587740951952684
-39.85  0.22584728950710667
-39.84  0.22581710812041733
-39.83  0.22578686525193203
-39.82  0.2257565607940121
-39.81  0.22572619463890706
-39.8   0.22569576667875516
-39.79  0.22566527680558351
-39.78  0.2256347249113083
-39.77  0.22560411088773488
-39.76  0.2255734346265584
-39.75  0.22554269601936372
-39.74  0.22551189495762586
-39.73  0.2254810313327101
-39.72  0.22545010503587254
-39.71  0.22541911595825986
-39.7   0.22538806399091013
-39.69  0.22535694902475262
-39.68  0.22532577095060846
-39.67  0.22529452965919064
-39.66  0.22526322504110433
-39.65  0.22523185698684722
-39.64  0.22520042538680982
-39.63  0.2251689301312756
-39.62  0.2251373711104214
-39.61  0.22510574821431775
-39.6   0.22507406133292898
-39.59  0.2250423103561137
-39.58  0.2250104951736248
-39.57  0.2249786156751102
-39.56  0.22494667175011282
-39.55  0.22491466328807083
-39.54  0.22488259017831816
-39.53  0.22485045231008477
-39.52  0.22481824957249674
-39.51  0.22478598185457688
-39.5   0.22475364904524478
-39.49  0.2247212510333173
-39.48  0.2246887877075088
-39.47  0.2246562589564315
-39.46  0.22462366466859565
-39.45  0.22459100473241017
-39.44  0.2245582790361826
-39.43  0.2245254874681198
-39.42  0.22449262991632774
-39.41  0.22445970626881256
-39.4   0.22442671641348028
-39.39  0.22439366023813742
-39.38  0.22436053763049132
-39.37  0.22432734847815042
-39.36  0.22429409266862463
-39.35  0.22426077008932568
-39.34  0.22422738062756745
-39.33  0.22419392417056627
-39.32  0.22416040060544154
-39.31  0.2241268098192157
-39.3   0.22409315169881477
-39.29  0.2240594261310688
-39.28  0.22402563300271208
-39.27  0.2239917722003836
-39.26  0.22395784361062732
-39.25  0.2239238471198926
-39.24  0.22388978261453468
-39.23  0.22385564998081484
-39.22  0.223821449104901
-39.21  0.22378717987286786
-39.2   0.2237528421706975
-39.19  0.22371843588427956

Currently, I get the following output:

However, I would like the grey shading to extend all the way to the x-axis.

Something like this?: https://tex.stackexchange.com/a/165078/1952 — Ignasi, May 15 '19 at 10:14
you use pgfplots not (pure) tikz. please correct question title accordingly. also add short results.dat with help of the filecontents package or other means. — Zarko, May 15 '19 at 10:45

score 1 · Accepted Answer · 2019-05-15T12:31:11.983

One possible way to do it.

\documentclass[tikz]{standalone}
\usepackage{filecontents}
\begin{filecontents*}{results.dat}
 x  s   
 -40.   4.032258064516129   
 -39.99 4.022984128316752   
 -39.98 4.013731521578736   
 -39.97 4.004500195245699   
 -39.96 3.9952901003740666  
 -39.95 3.9861011881328228  
 -39.94 3.976933409803266   
 -39.93 3.967786716778768   
 -39.92 3.958661060564457   
 -39.91 3.949556392777008   
 -39.9  3.9404726651444 
 -39.89 3.9314098295055957  
 -39.88 3.922367837810347   
 -39.87 3.9133466421189103  
 -39.86 3.9043461946018128  
 -39.85 3.8953664475395726  
 -39.84 3.8864073533224652  
 -39.83 3.8774688644502615  
 -39.82 3.86855093353199    
 -39.81 3.8596535132856657  
 -39.8  3.850776556538048   
 -39.79 3.8419200162244036  
 -39.78 3.833083845388234   
 -39.77 3.8242679971810394  
 -39.76 3.815472424862069   
 -39.75 3.8066970817980788  
 -39.74 3.7979419214630714  
 -39.73 3.789206897438054   
 -39.72 3.7804919634108067  
 -39.71 3.771797073175613   
 -39.7  3.763122180633034   
 -39.69 3.7544672397896375  
 -39.68 3.7458322047578068  
 -39.67 3.737217029755445   
 -39.66 3.728621669105734   
 -39.65 3.7200460772369466  
 -39.64 3.7114902086821457  
 -39.63 3.7029540180789593  
 -39.62 3.6944374601693513  
 -39.61 3.6859404897993984  
 -39.6  3.677463061918994   
 -39.59 3.6690051315816636  
 -39.58 3.6605666539442985  
 -39.57 3.6521475842669378  
 -39.56 3.6437478779125088  
 -39.55 3.635367490346601   
 -39.54 3.62700637713724    
 -39.53 3.618664493954633   
 -39.52 3.6103417965709457  
 -39.51 3.602038240860062   
 -39.5  3.593753782797362   
 -39.49 3.5854883784594715  
 -39.48 3.5772419840240355  
 -39.47 3.5690145557694977  
 -39.46 3.5608060500748504  
 -39.45 3.5526164234194137  
 -39.44 3.544445632382597   
 -39.43 3.5362936336436888  
 -39.42 3.528160383981598   
 -39.41 3.520045840274642   
 -39.4  3.5119499595003245  
\end{filecontents*}
\usepackage{pgfplots,mathtools} 
\usepgfplotslibrary{fillbetween}
\usepackage{amsmath,amssymb,bm}
\pgfplotsset{compat=newest}

\begin{document}

\pgfplotstableread{results.dat}{\Results}

\begin{tikzpicture}[]
    \begin{axis}[
%      width=\columnwidth,
%         height=0.618\columnwidth,
        ymode=log,
        xlabel style = {font=\Large, yshift=0.5ex},
        ylabel style = {font=\Large, yshift=-1.1ex},
        xlabel={SNR (\text{dB})},
        ylabel={MSE (\text{rad}$^2$)},
        xmin=-40,% xmax=15,  
        axis line style={line width=1pt},
        xticklabel style = {font=\Large,yshift=-0.2ex},
        yticklabel style = {font=\Large,xshift=-0.2ex},
        xtick={-40,-30,-20,-10,0,10},   
        xticklabels={-40,-30,-20,-10,0,10},
    ]   
    \addplot [name path=A,black, line width=1pt,fill=blue] table [x={x}, y={s}] {\Results}
    coordinate[pos=0] (p0) coordinate[pos=1] (p1);
\path[name path=B] (current axis.south-|p0) -- (current axis.south-|p1);  
    \addplot fill between [of=A and B];
    \end{axis}
\end{tikzpicture}

\end{document}

@Sid \addplot[fill=gray] fill between [of=A and B]; – May 15 '19 at 13:32 — , May 15 '19 at 13:32

score 0 · Answer 2 · answered May 15 '19 at 13:09

A small (mostly off-topic) variation of @marmot answer. You may liked it :-)

\documentclass[border=3mm]{standalone}
\usepackage{filecontents}
\usepackage{siunitx}
\usepackage{pgfplots}
\pgfplotsset{compat=1.16}
\usepgfplotslibrary{fillbetween}

\begin{filecontents}{test.csv}
  x     s
 -40.   4.032258064516129
 -39.99 4.022984128316752
 -39.98 4.013731521578736
 -39.97 4.004500195245699
 -39.96 3.9952901003740666
 -39.95 3.9861011881328228
 -39.94 3.976933409803266
 -39.93 3.967786716778768
 -39.92 3.958661060564457
 -39.91 3.949556392777008
 -39.9  3.9404726651444
 -39.89 3.9314098295055957
 -39.88 3.922367837810347
 -39.87 3.9133466421189103
 -39.86 3.9043461946018128
 -39.85 3.8953664475395726
 -39.84 3.8864073533224652
 -39.83 3.8774688644502615
 -39.82 3.86855093353199
 -39.81 3.8596535132856657
 -39.8  3.850776556538048
 -39.79 3.8419200162244036
 -39.78 3.833083845388234
 -39.77 3.8242679971810394
 -39.76 3.815472424862069
 -39.75 3.8066970817980788
 -39.74 3.7979419214630714
 -39.73 3.789206897438054
 -39.72 3.7804919634108067
 -39.71 3.771797073175613
 -39.7  3.763122180633034
 -39.69 3.7544672397896375
 -39.68 3.7458322047578068
 -39.67 3.737217029755445
 -39.66 3.728621669105734
 -39.65 3.7200460772369466
 -39.64 3.7114902086821457
 -39.63 3.7029540180789593
 -39.62 3.6944374601693513
 -39.61 3.6859404897993984
 -39.6  3.677463061918994
 -39.59 3.6690051315816636
 -39.58 3.6605666539442985
 -39.57 3.6521475842669378
 -39.56 3.6437478779125088
 -39.55 3.635367490346601
 -39.54 3.62700637713724
 -39.53 3.618664493954633
 -39.52 3.6103417965709457
 -39.51 3.602038240860062
 -39.5  3.593753782797362
 -39.49 3.5854883784594715
 -39.48 3.5772419840240355
 -39.47 3.5690145557694977
 -39.46 3.5608060500748504
 -39.45 3.5526164234194137
 -39.44 3.544445632382597
 -39.43 3.5362936336436888
 -39.42 3.528160383981598
 -39.41 3.520045840274642
 -39.4  3.5119499595003245
\end{filecontents}

\begin{document}
\begin{tikzpicture}
\begin{semilogyaxis}[
        axis on top,
        log ticks with fixed point,
        %
        xlabel={SNR (dB)},
        ylabel={MSE (\si{rad^2})},
        xtick={-40,-39.9,...,-39,5},
        ticklabel style={font=\footnotesize},
        xmin=-40, xmax=-39.4,
        enlargelimits=0]
\addplot[line width=1pt,
         name path=A] table[x=x,y=s] {test.csv};
\path [name path=B] (\pgfkeysvalueof{/pgfplots/xmin},0) --
                    (\pgfkeysvalueof{/pgfplots/xmax},0);
\addplot [gray!30] fill between [of=A and B];
\end{semilogyaxis}
\end{tikzpicture}
\end{document}

Fill area below curve from filecontents in PGFPlots

2 Answers2