D5 Annex report WP 3: ETIS Database methodology ... - ETIS plus

D5 Annex WP 3: DATABASE METHODOLOGY AND DATABASE USER MANUAL –
FREIGHT TRANSPORT DEMAND
PT 8 0 4 22 14 0 1 3 0 53
Total 3,873 109 2,394 7,007 7,836 163 851 1,327 908 24,468
By calculating the cell errors, and simply shading the cells involving neighbouring countries, it
is fairly obvious that the errors are strongly correlated with distance, i.e. this method tends to
under­estimate flows where the distance is small. It would follow that if the matrix is seeded
with initial values that reflect distance, the estimation accuracy should improve.
Analysis of Errors: Actual vs Estimated (based on 3 Digit Furnessing)
F NL D IT UK IRL DK EL PT
F 0 42,209 ­41,829 ­11,006 1,430 23,230 27,821 ­28,955 ­12,901
NL 23,620 0 ­47,164 9,743 ­17,190 13,088 ­7,726 25,732 ­101
D 36,611 ­83,844 0 ­10,916 14,605 39,126 ­44,895 42,729 6,585
IT ­125,318 39,107 39,728 0 53,459 21,656 17,066 ­46,671 972
UK 43,433 ­4,899 72,356 3,935 0 ­102,528 3,641 ­17,368 1,430
IRL 6,908 7,933 24,950 4,961 ­59,099 0 2,590 9,455 2,301
DK 12,743 ­1,494 ­25,376 3,438 ­74 3,179 0 6,277 1,307
EL 1,891 ­4,015 665 ­2,356 2,596 412 395 0 413
PT 347 5,048 ­23,780 2,208 4,396 1,846 1,119 8,816 0
An allowance for distance has been introduced by using the gravity model described above.
The amoeba algorithm was used to calculate ‘n’ and ‘m’ parameters, and then the gravity
function was used to seed the matrix.
A Solution by Furnessing a Seeded Matrix at the 2 Digit Level
F NL D IT UK IRL DK EL PT Total
F 0 63,087 257,750 87,545 263,764 25,400 26,260 75,374 17,006 816,186
NL 131,527 0 240,474 30,627 171,076 16,474 17,032 48,887 11,030 667,127
D 469,180 209,961 0 130,518 294,419 47,174 81,149 139,989 31,584 1,403,972
IT 294,021 49,339 240,812 0 150,721 29,562 30,563 145,966 19,793 960,777
UK 190,362 59,222 116,732 32,388 0 31,846 19,788 56,798 12,815 519,952
IRL 24,128 10,026 22,094 6,282 60,295 0 4,173 11,978 2,703 141,677
DK 18,144 9,218 44,234 6,784 27,205 4,359 0 12,935 2,918 125,798
EL 4,646 1,445 4,740 3,847 4,850 1,116 1,154 0 747 22,545
PT 17,409 4,069 12,369 6,033 13,656 2,912 3,011 8,643 0 68,102
Total 1,149,417 406,366 939,204 304,023 985,986 158,844 183,131 500,570 98,596 4,726,136
If the errors from this method are examined in the same way, the correlation between the error
sign and the distance can be seen to be lower.
Analysis of Errors (Tonnes): Actual vs Seeded Result
F NL D IT UK IRL DK EL PT
F 0 20,441 ­47,620 6,022 51,308 19,666 17,481 ­52,155 ­15,143
NL ­25,539 0 11,018 ­7,000 11,900 8,858 ­14,387 17,589 ­2,439
D 24,565 ­35,514 0 903 ­69,121 29,673 ­25,232 68,126 6,602
IT ­65,187 11,445 47,564 0 20,084 23,651 15,850 ­56,365 2,958
UK 69,301 2,322 24,388 ­5,036 0 ­88,916 1,327 ­6,399 3,012
58
Document2
27 May 2004