Fit graph into specified dimensions pgfplots

Question

I'm trying to get my graph to fit inside of the graph's dimensions (4in by 7.5in). I want the ymin of the graph to be the minimum y value of all my points and the ymax value the maximum y value for all of my points (so that my graph fits snugly but doesn't get cut off).

My graph seems to go outside of the boundaries. I've tried to use enlargelimits=true but it adds too much whitespace.

I've also tried enlarge y limits={true, abs value=0.75}, and many different variations, however it doesn't appear to affect the graph at all.

I could use xmin and xmax but I have ~20 graphs, and I don't really want to change each separately.

\begin{tikzpicture}
    \begin{axis}[
        xmin=1,
        enlarge y limits={true, abs value=0.75},
        xlabel=Atomic Number,
        ylabel=Atomic Radius $(in$ $pm)$,
        width=7.5in,
        height=4in,
        enlargelimits = false,
        extra x ticks={1,84},
        title={\large Atomic Number vs. Atomic Radius $(in$ $pm)$}]
    \addplot[smooth,mark=none,black] plot coordinates {
(1,37.1) (2,31) (3,152) (4,112) (5,85) (6,77.2) (7,70) (8,73) (9,72) (10,71) (11,186) (12,160) (13,143) (14,117.6) (15,110) (16,103) (17,100) (18,98) (19,227) (20,197) (21,162) (22,147) (23,134) (24,128) (25,127) (26,126) (27,125) (28,124) (29,128) (30,134) (31,135) (32,122.3) (33,120) (34,119) (35,114) (36,112) (37,248) (38,215) (39,180) (40,160) (41,146) (42,139) (43,136) (44,134) (45,134) (46,137) (47,144) (48,151) (49,167) (50,140.5) (51,140) (52,142) (53,133) (54,131) (55,265) (56,222) (57,187) (58,182) (59,182) (60,181) (61,183) (62,180) (63,208) (64,180) (65,177) (66,178) (67,176) (68,176) (69,176) (70,193) (71,174) (72,159) (73,146) (74,139) (75,137) (76,135) (77,136) (78,139) (79,144) (80,151) (81,170) (82,146) (83,150) (84,168)     };

\end{axis}
\end{tikzpicture}

Answer 1

Setting enlargelimits=false, as you've done, causes PGFPlots to adjust the limits so that all the data points are just visible. However, this does not take into account the overshooting introduced by the smooth style. So you'll need to adjust the limits, using something like (as you've attempted) enlarge y limits={true, abs value=5}. However, you also need to remove the enlargelimits=false, otherwise you'll override the setting.

I would recommend not using the smooth style, however: As you've noticed, it doesn't accurately represent the data due to the overshooting. Also, smoothing the data makes it seem like you have much more data than you actually do, so it's not entirely honest.