Buenas Jorge:
Creo que esto es lo que quieres.
Un saludo.
> d <- matrix(c(6819,0.718,0,0,0,0,0,0,0,0,0,0,0,0, 6820,3.806,1.66,1.66,1.66,1.66,1.66,1.66,1.66,1.66,1.66,1.66,1.66,1.66, 6821,0.036,0,0,0,0,0,0,0,0,0,0,0,0, 6822,3.806,0.61,0.61,0.61,0.61,0.61,0.61,0.61,0.61,0.61,0.61,0.61,0.62, 6823,0.963,0.19,0.19,0.19,0.19,0.19,0.19,0.19,0.19,0.19,0.19,0.19,0.25, 6824,0,0,0,0,0,0,0,0,0,0,0,0,0), ncol=14, byrow=TRUE)
> colnames(d) <- c("PIX","X1990","X1991","X1992","X1993","X1994","X1995","X1996","X1997","X1998","X1999","X2000","X2001","X2002")
> d <- data.frame(d)
> d
PIX X1990 X1991 X1992 X1993 X1994 X1995 X1996 X1997 X1998 X1999 X2000 X2001
1 6819 0.718 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
2 6820 3.806 1.66 1.66 1.66 1.66 1.66 1.66 1.66 1.66 1.66 1.66 1.66
3 6821 0.036 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
4 6822 3.806 0.61 0.61 0.61 0.61 0.61 0.61 0.61 0.61 0.61 0.61 0.61
5 6823 0.963 0.19 0.19 0.19 0.19 0.19 0.19 0.19 0.19 0.19 0.19 0.19
6 6824 0.000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
X2002
1 0.00
2 1.66
3 0.00
4 0.62
5 0.25
6 0.00
> reshape(d, varying = list(2:14), direction='long')
PIX time X1990 id
1.1 6819 1 0.718 1
2.1 6820 1 3.806 2
3.1 6821 1 0.036 3
4.1 6822 1 3.806 4
5.1 6823 1 0.963 5
6.1 6824 1 0.000 6
1.2 6819 2 0.000 1
2.2 6820 2 1.660 2
3.2 6821 2 0.000 3
4.2 6822 2 0.610 4
5.2 6823 2 0.190 5
6.2 6824 2 0.000 6
1.3 6819 3 0.000 1
2.3 6820 3 1.660 2
3.3 6821 3 0.000 3
4.3 6822 3 0.610 4
5.3 6823 3 0.190 5
6.3 6824 3 0.000 6
1.4 6819 4 0.000 1
2.4 6820 4 1.660 2
3.4 6821 4 0.000 3
4.4 6822 4 0.610 4
5.4 6823 4 0.190 5
6.4 6824 4 0.000 6
1.5 6819 5 0.000 1
2.5 6820 5 1.660 2
3.5 6821 5 0.000 3
4.5 6822 5 0.610 4
5.5 6823 5 0.190 5
6.5 6824 5 0.000 6
1.6 6819 6 0.000 1
2.6 6820 6 1.660 2
3.6 6821 6 0.000 3
4.6 6822 6 0.610 4
5.6 6823 6 0.190 5
6.6 6824 6 0.000 6
1.7 6819 7 0.000 1
2.7 6820 7 1.660 2
3.7 6821 7 0.000 3
4.7 6822 7 0.610 4
5.7 6823 7 0.190 5
6.7 6824 7 0.000 6
1.8 6819 8 0.000 1
2.8 6820 8 1.660 2
3.8 6821 8 0.000 3
4.8 6822 8 0.610 4
5.8 6823 8 0.190 5
6.8 6824 8 0.000 6
1.9 6819 9 0.000 1
2.9 6820 9 1.660 2
3.9 6821 9 0.000 3
4.9 6822 9 0.610 4
5.9 6823 9 0.190 5
6.9 6824 9 0.000 6
1.10 6819 10 0.000 1
2.10 6820 10 1.660 2
3.10 6821 10 0.000 3
4.10 6822 10 0.610 4
5.10 6823 10 0.190 5
6.10 6824 10 0.000 6
1.11 6819 11 0.000 1
2.11 6820 11 1.660 2
3.11 6821 11 0.000 3
4.11 6822 11 0.610 4
5.11 6823 11 0.190 5
6.11 6824 11 0.000 6
1.12 6819 12 0.000 1
2.12 6820 12 1.660 2
3.12 6821 12 0.000 3
4.12 6822 12 0.610 4
5.12 6823 12 0.190 5
6.12 6824 12 0.000 6
1.13 6819 13 0.000 1
2.13 6820 13 1.660 2
3.13 6821 13 0.000 3
4.13 6822 13 0.620 4
5.13 6823 13 0.250 5
6.13 6824 13 0.000 6