20 Nov 2007

## Official Asymptote example – westnile

 (Compiled with Asymptote version 2.14svn-r5318)
/* This code comes from The Official Asymptote Gallery */

import graph;

size(9cm,8cm,IgnoreAspect);
string data="westnile.csv";

file in=input(data).line().csv();

string[] columnlabel=in;

real[][] A=in.dimension(0,0);
A=transpose(A);
real[] number=A[0], survival=A[1];

path g=graph(number,survival);
draw(g);

scale(true);

xaxis("Initial no.\ of mosquitoes per bird ($S_{M_0}/N_{B_0}$)",
Bottom,LeftTicks);
xaxis(Top);
yaxis("Susceptible bird survival",Left,RightTicks(trailingzero));
yaxis(Right);

real a=number[0];
real b=number[number.length-1];

real S1=0.475;
path h1=(a,S1)--(b,S1);
real M1=interp(a,b,intersect(h1,g)[0]);

real S2=0.9;
path h2=(a,S2)--(b,S2);
real M2=interp(a,b,intersect(h2,g)[0]);

labelx("$M_1$",M1);
labelx("$M_2$",M2);

draw((a,S2)--(M2,S2)--(M2,0),Dotted);
draw((a,S1)--(M1,S1)--(M1,0),dashed);

pen p=fontsize(10pt);

real y3=0.043;
path reduction=(M1,y3)--(M2,y3);
draw(reduction,Arrow,TrueMargin(0,0.5*(linewidth(Dotted)+linewidth())));

arrow(shift(-20,5)*Label(minipage("\flushleft{\begin{itemize}\item[1.]
Estimate proportion of birds surviving at end of season\end{itemize}}",100),
align=NNE),
(M1,S1),NNE,1cm,p,Arrow(NoFill));

arrow(shift(-24,5)*Label(minipage("\flushleft{\begin{itemize}\item[2.]
(M1,0),NE,2cm,p,Arrow(NoFill));

arrow(shift(20,0)*Label(minipage("\flushleft{\begin{itemize}\item[3.]
Determine desired bird survival for next season\end{itemize}}",90),align=SW),
(M2,S2),SW,arrowlength,p,Arrow(NoFill));

arrow(shift(8,-15)*Label(minipage("\flushleft{\begin{itemize}\item[4.]
Calculate required proportional reduction in mosquitoes\end{itemize}}",90),
align=NW),
point(reduction,0.5),NW,1.5cm,p,Arrow(NoFill));



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