Create virtual globes from Cartography Guild Mercator world maps

[MollyJ]

Create virtual globes from Cartography Guild Mercator world maps
using open source tools available on Linux.
(There may be ways to use these applications on Windows, please post your solutions/corrections)


This procedure converts the big Mercator Guild world map into an adjustable perspective png image
of a globe ready for pasting into a nice background illustration using 'MMPS' and 'ImageMagick' on Linux.

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ImageMagick is probably pre-installed on your Lunux distribution else, use your package manager to get it.
I use ImageMagick Legacy version 6. The newer version 7 has slightly different syntax. Edit as necessary.

Download and compile MMPS from:
http://www.users.globalnet.co.uk/~arcus/mmps/
Follow Matthew's instructions carefully.

Matthew's choice of executable names is too easily confused with pre-existing unix tools, so change the name as follows:
$ sudo cp the_folderyou_unzipped/mmps-master/project /usr/local/bin/mproject

The MMPS Suite is composed of 6 executables but we only need "mproject"
The six executables are: "project", "addgrid", "circularize", "stars", "combine", and "testimage"

Some details:
The original Mercator image without margins is 4000x2000
The colour of the ocean is #024048 (02:64:72 decimal)
The intermediate background colour is chroma_key_green #00b140 (0:177:64 decimal)

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(If all you want is a globe, these four commands are all you need)

** ImageMagick -- This crops and converts to ppm format as MMPS only accepts PortablePixMap
$ convert Guildworld_4K.jpg -crop 4000X2000+48+48 Guildworld_cropped.ppm

** MMPS -- convert from Mercator to Plate-Carree and fill in the missing ocean colour (02:64:72)
$ mproject -i mercator -h 2000 -w 4000 -adjust -bg 02:64:72 -f Guildworld_cropped.ppm > Guildworld_latlon.ppm

** MMPS -- test globe image with chroma key background
$ mproject perspective -lat 23 -long 30 -x 6 -sun -date 168 -time 3.83 -bg 0:177:64 -f Guildworld_latlon.ppm | display

** MMPS -- create globe with transparent background for pasting into other images:
$ mproject perspective -lat 23 -long 30 -x 6 -sun -date 168 -time 3.83 -bg 0:177:64 -f Guildworld_latlon.ppm > temp_GG.ppm
$ convert temp_GG.ppm -transparent "rgb(0,177,64)" Guild_Globe.png

Notes:
The top left is Mercator, the right is Plate-Carree (Equirectangular)
Edit the last MMPS command to change lat, long, date, and time. If you do not want the shadow, edit out "-sun"
MMPS is "Matthew's Map Projection Suite"
Once you have created the Plate-Carree projection, you can use it in most any 3d imaging software; Blender, Pov-ray, Xplanet, etc.

-- Molly J.