Robert Bosch has created a fascinating series of instances of the traveling salesman problem (TSP) that provide continuous-line drawings of well-known pieces of art. Techniques for developing such point sets have evolved over the past several years through work of Bosch and Craig Kaplan.

One of Bosch's instances is the 100,000-point set for the Mona Lisa TSP Challenge. Additional instances range in size up to 200,000 cities, providing a difficult test for TSP solution methods. The data sets are specified in TSPLIB format. We thank Bob for making these beautiful problems available to the research community.

Original Art Data Set Cities
da Vinci's Mona Lisa mona-lisa100K.tsp 100,000
van Gogh's Self Portrait 1889 vangogh120K.tsp 120,000
Botticelli's The Birth of Venus venus140K.tsp 140,000
Velazquez's Juan de Pareja pareja160K.tsp 160,000
Courbet's The Desperate Man courbet180K.tsp 180,000
Vermeer's Girl with a Pearl Earring earring200K.tsp 200,000

mona-lisa100K.tsp
vangogh120.tsp
venus140K.tsp
pareja160K.tsp
courbet180K.tsp
earring200K.tsp

The following papers discuss the mathematics behind the selection of city locations for these TSP Art instances.

Pretty examples of other TSP drawings can be found on Robert Bosch's TSP Art page and on the page of Craig Kaplan.

The best known results for the TSP Art instances are given in the table below. The tour length, given in the Best Tour column, is a link to the tour in TSPLIB format. I would be happy to post any improvements you find.

Problem Best Tour Source of Tour
mona-lisa100K 5,757,191 Yuichi Nagata (2009)
vangogh120K 6,543,609 Kazuma Honda, Yuichi Nagata, Isao Ono (2013)
venus140K 6,810,665 Yuichi Nagata (2011)
pareja160K 7,619,953 Yuichi Nagata (2011)
courbet180K 7,888,731 Kazuma Honda, Yuichi Nagata, Isao Ono (2013)
earring200K 8,171,677 Yuichi Nagata (2011)

Notes

The vangogh120k and courbet180k tours were received from Yuichi Nagata on July 16, 2019. The tours are reported in the paper A Parallel Genetic Algorithm with Edge Assembly Crossover for 100,000-City Scale TSPs from 2013 by Honda, Nagata, and Ono. The previous best tours for these instances, found by Yuichi Nagata in 2011, had lengths 6,543,610 and 7,888,733, respectively.

Thanks to Emilio Bendotti, Francesco Cavaliere and Matteo Fischetti for pointing me to the Honda et al. paper. The Bendotti-Cavaliere-Fischetti team themselves found a tour of length 7,888,732 for courbet180k on July 13, 2019, starting from Nagata's 7,888,733 tour.