After considerable effort I found a better method to calculate the color of blocks that have been painted. Here are the results: maps of several of the most popular worlds, latest good (non-griefed) versions I could find as of April 6th, 2013.

To include any of these on another page, use the Scrolling Map template. For example if the name of the map image file is "Seijuurou.72416262.00b-20130329.jpg", wikitext is:

 {{Scrolling Map|Seijuurou.72416262.00b-20130329.jpg|580|580}}



Map of Ataru.65196197 (my version of "Mega City Tokyo Extended", version 08, dated 2013 April 7th)


DIRECT CITY 1.9.9-20130406

Map of "DIRECT CITY 1'9'9", from 2013 April 6th (wikia page: Direct_City)


Hogwarts By Brendan V7-20130406

Map of "Hogwarts By Brendan V7" from 2013 April 6th (wikia page: Hogwarts_By_Brendan)


I did two versions of Luxury Villas, a world whose original creator asked others to take over:

Luxury Villas v8 Contemeporary Estate-20130406

Map of "Luxury Villas v8 Contemeporary Estate" from 2013 April 6th (wikia page: Luxury_VIllas_by_Henry_Rhodes)


Luxury Villas v13 New School-20130406

Map of "Luxury Villas v13 New School" from 2013 April 6th (wikia page: Luxury_VIllas_by_Henry_Rhodes)


Massive Tree .MiniGames. by TASKS-20130331

Map of "Massive Tree 'MiniGames' by TASKS" from 2013 March 31 (wikia page: Massive_Tree_by_Tasks)


Metropolis 2150 v27 xXRTXx-20130403

Map of "Metropolis 2150 v27 xXRTXx" from 2013 April 3rd (wikia page: Metropolis_2150_by_Tzekoo)


Olympic Metropolis Port Angkor1-20130406

Map of "Olympic Metropolis Port Angkor1" from 2013 April 6th



Map of "MEGA CITY TOKYO EXTENDED V4" (also posted as "Seijuurou'72416262'00b") from 2013 March 27th (wikia page: Mega_City_Tokyo_(Extended))


The Islands Retro by Bnm786-20130303

Map of "The Islands Retro by Bnm786" from 2013 March 3rd (wikia page: The_Islands)


THE OCTOGON Farmlands by SS-20130406

Map of "THE OCTOGON Farmlands by SS" from 2013 April 6th (wikia page: THE_OCTOGON)


VENTURE and UTOPIA v9 by AJ .235711.-20130405

Map of "VENTURE and UTOPIA v9 by AJ '235711' " from 2013 April 5th (wikia page: Venture_and_Utopia)


Video game museum with additions-20130211

Map of "Video game museum with additions" from 2013 Feb 11th (wikia page: Video_Game_Museum)


Village With Fort V15 by Dblcut3-20130316

Map of "Village With Fort V15 by Dblcut3" from 2013 March 16th (wikia page: Village With Fort by Dblcut3)