Hints for the Use of Map Labeling Heuristics
We offer you a choice of
Map Labeling algorithms
. The following remarks are intended to help you to make some observations during testing.
Some people have complained that the indices attached to say small random examples did overlap. However this is only the case in the display of the newly generated point set. You must then chose one of the algorithms offered below, and press the
button to have the instance labeled properly. The indices shown initially are all just placed above the sites. They are meant to help you to find the coordinates of a site in the INPUT field, so that you can change the position of a specific site. For reasons of legibility, these indices are only displayed for small problem sizes.
Some brousers (netscape for instance) cause problems with input via TEXTAREA, so we used an INPUT field in the FORM in which we ask you for coordinates. If you fill in your own ones, make sure they are seperated by blanks - not carriage returns.
normally produces results which are only slightly better than 50% of the
. This is intolarably bad in practice. On the other hand twice the label size found by
gives a good upper bound for the
. This is important to estimate the quality of the heuristics for large point sets where the exact solvers either run out of memory or need ages to come up with the optimal solution.
To see the differences between the
examples for your tests. On
problems they all find solutions very close to 100% of the optimal label size. This of course is an interesting fact in its own right.
examples even bring
down to solutions no better than its quality guaranty of 50% of the optimal solution.
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