reference line in plot

hello everyone

hope u r fine

actually i am plotting a using implict command and i want to make my z axis as a prominant line as i hav done it here.

code:

clear
clc
close
%% Receivers coordinates

lats = [34.1989 34.0105 34.067894 34.1166 34.0151]; longs = [72.0231 71.9876 71.992783 72.0216 71.5249];
[x,y] = grn2eqa(lats,longs,[34.1166, 72.0216])  
% x=[8 0 -8 0 ].*100; %%x=[x_1 x_2 x_3 x_p]
% x(5) = -x(5); y(5) = -y(5);
% y=[-4 8 -4 5].*100;  %%y=[y_1 y_2 y_3 y_p]
z=[0 0 0 0];   %%z=[z_1 z_2 z_3 z_p]
c=2.997924580*10^8;

%% Source TDOA calculation

z_s=0.0098;
t1 = (sqrt((x(5)-x(4))^2+(y(5)-y(4))^2+(z_s-z(4))^2)-sqrt((x(5)-x(1))^2+(y(5)-y(1))^2+(z_s-z(1))^2))/c
t2 = (sqrt((x(5)-x(4))^2+(y(5)-y(4))^2+(z_s-z(4))^2)-sqrt((x(5)-x(2))^2+(y(5)-y(2))^2+(z_s-z(2))^2))/c
t3 = (sqrt((x(5)-x(4))^2+(y(5)-y(4))^2+(z_s-z(4))^2)-sqrt((x(5)-x(3))^2+(y(5)-y(3))^2+(z_s-z(3))^2))/c

%% Source localization

syms xs ys zs     %our unknowns
eqn1 = sqrt((xs-x(4))^2+(ys-y(4))^2+(zs-z(4))^2)-sqrt((xs-x(1))^2+(ys-y(1))^2+(zs-z(1))^2)-(c*t1);
eqn2 = sqrt((xs-x(4))^2+(ys-y(4))^2+(zs-z(4))^2)-sqrt((xs-x(2))^2+(ys-y(2))^2+(zs-z(2))^2)-(c*t2);
eqn3 = sqrt((xs-x(4))^2+(ys-y(4))^2+(zs-z(4))^2)-sqrt((xs-x(3))^2+(ys-y(3))^2+(zs-z(3))^2)-(c*t3);
sol = solve([eqn1, eqn2, eqn3], [xs ys zs]);


figure(1)
% fimplicit3(eqn1,[-0.008 0.001 -0.002 0.0015 0 0.015],'EdgeColor','none','FaceAlpha',.5)
fimplicit3(eqn1,[-0.008 0.001 -0.002 0.0015 -0.015 0.015],'EdgeColor','b','FaceAlpha',0)
hold on
fimplicit3(eqn2,[-0.008 0.001 -0.002 0.0015 -0.015 0.015],'EdgeColor','g','FaceAlpha',0)
fimplicit3(eqn3,[-0.008 0.001 -0.002 0.0015 -0.015 0.015],'EdgeColor','y','FaceAlpha',0)
% fimplicit3(eqn2,[-0.008 0.001 -0.002 0.0015 -0.015 0.015],'EdgeColor','none','FaceAlpha',.5)
% fimplicit3(eqn3,[-0.008 0.001 -0.002 0.0015 -0.015 0.015],'EdgeColor','none','FaceAlpha',.5)



%%
m = 1;
for n = 1:length(sol.xs)
possibleSol(1,m) = double(sol.xs(n));
 
possibleSol(2,m) = double(sol.ys(n));
 
possibleSol(3,m) = double(sol.zs(n))
m=m+1;
end
%%

%%Filtering Results

%idx = all(possibleSol < 0) | all(imag(possibleSol) ~=0)
idx = possibleSol(3,:) < 0 | any(imag(possibleSol) ~=0)
possibleSol(:, idx) = [];
[lat,long] = eqa2grn(possibleSol(1),possibleSol(2),[34.1166, 72.0216])



%Plotting on 3D coordinates

% fprintf('Xs=%g\n', possibleSol(1,1)); quiver3
% fprintf('Ys=%g\n', possibleSol(2,1));
% fprintf('Zs=%g\n', possibleSol(3,1));
% scatter3(x, y, z, 'o');
% hold on
% scatter3(possibleSol(1,1), possibleSol(2,1), possibleSol(3,1), '+');
% hold off
% legend({'Receivers', 'Source'})


figure(2)
hold on
grid on
view(3);
plot3(x(1:4),y(1:4),z, 'ro', 'LineWidth', 2, 'MarkerSize', 10);
plot3(possibleSol(1),possibleSol(2),possibleSol(3), 'b+', 'LineWidth', 4, 'MarkerSize', 10)
plot3(x(5),y(5),z_s,'g+', 'LineWidth', 2, 'MarkerSize', 10)
legend({'Receivers', 'Source','exactvalue'})

[源樹 上林]

zline ... is not available, how about this?

x = xlim;
y = ylim;
y = [y(2) y(2)];
z = [0 0];
hold on
plot3(x, y, z)
hold off