Re: [Rd] typo in `eurodist'

From: Jari Oksanen <jarioksa_at_sun3.oulu.fi>
Date: Fri 09 Dec 2005 - 08:02:13 GMT

Dear all,

There really seem to be many exciting issues in spelling and in detecting spelling errors. However, a more disturbing feature in 'eurodist' to me is that the distances seem to be wrong. There are several cases where the triangle inequality is violated so that a trip from A to B is shorter when you make a detour via X instead of going directly (see require(fortunes); fortune("eurodist") for an example). A quick look revealed that you can find such a shorter detour for 104 of 210 "distances" of 'eurodist'. There is no guarantee that these shortest path distances would be correct, but at least they are metric.

Just for fun, here are the differences between actual eurodist's and shortest paths among the towns in the eurodist data:

                Athens Barcelona Brussels Calais Cherbourg
Barcelona         1036
Brussels           635         0
Calais             705        13        0
Cherbourg          819         0        0      0
Cologne            448       139        0      0         0
Copenhagen         507       459      525    537       545
Geneva             879         0        0      0         0
Gibralta          1037         0        0      0         2
Hamburg            438       214        0      0         0
Hook of Holland    530         0        0      0         0
Lisbon            1623         1      216    135         0
Lyons             1022         0        0      0         0
Madrid            1036         0        0      0         0
Marseilles        1037         0        1      0         0
Milan              879        41        0     10        92
Munich             445        61        0     26         0
Paris              798         0        0      0         0
Rome                 0         0        0      9        91
Stockholm          508       459      525    537       546
Vienna               0        70       32     35         0
                Cologne Copenhagen Geneva Gibralta Hamburg
Barcelona
Brussels
Calais
Cherbourg
Cologne
Copenhagen          222
Geneva              790        300
Gibralta              0        499      0
Hamburg               0          0      0       49
Hook of Holland       0          0     46        0       0
Lisbon              398        662    600        0     334
Lyons                 0        327      0        0       0
Madrid               26        499      0        0      48
Marseilles            1        327      0        0       0
Milan                 0        171      0       40     102
Munich                0          0      0       89       0
Paris                 0        450      0        0       0
Rome                  0         98     81        0      29
Stockholm           215          0    300      539       0
Vienna                0          0      0       70       0
                Hook of Holland Lisbon Lyons Madrid Marseilles
Barcelona
Brussels
Calais
Cherbourg
Cologne
Copenhagen
Geneva
Gibralta
Hamburg
Hook of Holland
Lisbon                      240
Lyons                         1      0
Madrid                        0      0     0
Marseilles                    1    264     0      0
Milan                         1    744     0    115          0
Munich                        0    670    65     70        160
Paris                         0    150     0      0          1
Rome                          0    608   134      1          0
Stockholm                   581    272   327    539        327
Vienna                        0    672    70     41          0
                Milan Munich Paris Rome Stockholm
Barcelona
Brussels
Calais
Cherbourg
Cologne
Copenhagen
Geneva
Gibralta
Hamburg
Hook of Holland
Lisbon
Lyons
Madrid
Marseilles
Milan
Munich              0
Paris              57      0
Rome                0     29    91
Stockholm         171      0   451  105
Vienna            139      0     0    0         1

It seems that "marginal" towns (Athens, Lisbon, Stockholm, Copenhagen) have largest discrepancies.

It also seems that the names are not 'localized', but weird English forms are used for places like KÝbenhavn and Wien so dear to the R core developers.

cheers, jari oksanen



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https://stat.ethz.ch/mailman/listinfo/r-devel Received on Fri Dec 09 19:07:47 2005

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