import matplotlib.pyplot as plt
from statistics import mean
import importation

x, y, t = importation.Latispro('fichier.txt')
N=len(x)
deltat=t[1]-t[0]
print("delta (s) = ",deltat)

Vx=[0]*N
Vy=[0]*N
deltaVx=[0]*N
deltaVy=[0]*N
deltaV=[0]*N

for i in range (0,N-1):
    Vx[i]=(x[i+1]-x[i])/deltat
    Vy[i]=
    plt.quiver(x[i],y[i],Vx[i],Vy[i], scale=15,color="b",angles="xy",units="xy")

for i in range (0,N-2):
    deltaVx[i]=
    deltaVy[i]=
    deltaV[i]=(deltaVx[i]*deltaVx[i]+deltaVy[i]*deltaVy[i])**0.5
    plt.quiver(x[i],y[i],deltaVx[i],deltaVy[i], scale=5,color="r",angles="xy",units="xy")

plt.plot(x,y,"b+") # tracé de la courbe c = f(t) (bleu, marque +, points non reliés)
plt.xlabel("x (m)") # légende abscisses
plt.ylabel("y (m)") # légende ordonnées
plt.axis("equal") # repère orthonormé
plt.title("Trajectoire y=f(x)") # titre

plt.show() # affichage des courbes

del deltaV[N-2:N]
deltaVmoy=mean(deltaV)
print("deltaV (m/s) = ",deltaVmoy)