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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thumbs44.jpg
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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.

[MollyJ]

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This set of commands creates a seamless transparent polar caps layer for the Plate-Carree map
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ice_cap-layer.png
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---create seed ice circle (ice_cap-00.png)
$ convert -size 4000x300 canvas:transparent -stroke white -fill white -draw 'circle 2000,150 2000,40' ice_cap-00.png

---create white undermask
$ convert -size 4000x300 canvas:white cap-white-BG-00.png

---NORTH---
---create rough coastlines from seed circle NORTH
$ convert ice_cap-00.png -alpha extract -virtual-pixel black -spread 100 -blur 0x3 -threshold 50% -spread 1 -blur 0x.7 ice_cap-mask-north.png
---apply NORTH rough mask to white layer
$ convert cap-white-BG-00.png ice_cap-mask-north.png -alpha off -compose Copy_Opacity -composite ice_cap-north.png

---SOUTH---
---create rough coastlines from seed circle SOUTH
$ convert ice_cap-00.png -alpha extract -virtual-pixel black -spread 100 -blur 0x3 -threshold 50% -spread 1 -blur 0x.7 ice_cap-mask-south.png
---apply SOUTH rough mask to white layer
$ convert cap-white-BG-00.png ice_cap-mask-south.png -alpha off -compose Copy_Opacity -composite ice_cap-south.png

--- north ice cap polar to equirectangular (4000 x 300)
$ convert ice_cap-north.png -virtual-pixel Black -distort DePolar 0 ice_cap-north-Q.png
--- south ice cap polar to equirectangular (4000 x 300)
$ convert ice_cap-south.png -virtual-pixel Black -distort DePolar 0 ice_cap-south-Q.png

--- create 4000 x 2000 transparent layer and add icecaps
$ convert -size 4000x2000 canvas:transparent ice_cap-south-Q.png -composite -flip -flop big_cap-1.png
$ convert big_cap-1.png ice_cap-north-Q.png -composite ice_cap-layer.png

$ gimp -- manually embellish this transparent ice_cap-layer.png

--- composite the ice onto the map
$ convert Guildworld_latlon.ppm ice_cap-layer.png -composite Guildworld_latlon-ice.ppm

--- TEST GLOBE WITH POLAR CAPS
$ mproject perspective -lat +23 -long 30 -x 8 -sun -date 168 -time 3.83 -f Guildworld_latlon-ice.ppm | display


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[MollyJ]

Forgot to add the final image.


latlon_01-ice.jpg

[MollyJ]

Adding Atmosphere to your Guild Planet
atm-dialog.jpg
Add "Atmosphere" to your Guild planet with Gimp layers. You can use the attached transparency for a quick one step process or use the layer mask for more flexibility. Add a light purple hue or colour gradient for realism.
The only tedious part is lining up the thin horizon ring in the mask with the edge of the globe. lots of scaling and fine tuning here.

atm-trnsp.png atm-trnsp-mask.png

[MollyJ]

Adding clouds to your Guild Plant
cloudyworld-tut.jpg
Add clouds to your Guild planet with Gimp layers. You can use the attached transparency for a quick one step process or use the layer mask for more flexibility. Add hue or colour gradient for alien/fantasy effects. More cloud maps in Plate-Carree projection are available online.
cloud-map-mask.png cloud-map-transp.png

[johnvanvliet]

I have not seen MMPS in YEARS , i found it a long time ago
Also i run linux , OpenSUSE to be precise

however i use Blender or Celestia to make the globe image

[MollyJ]

hallo johnvanvliet ,

I have been trying to find anything similar to MMPS that will quickly re-project maps. Can Celestia convert Mercator to Plate-Carree? I tried using it once but couldn't stop it crashing. I'm also looking for a small globe viewer. something that would take in a map and show a globe that can be turned by dragging the mouse. Or maybe set it rotating in an animated gif. There are gigantic applications like gis but they are unwieldy. I haven't used Blender but I have Pov-ray working nicely. I will post a Guild.pov script in a day or two with an image and notes.

--Molly_J

povguild.jpg

[Turambar]

hallo johnvanvliet ,

Can Celestia convert Mercator to Plate-Carree? I tried using it once but couldn't stop it crashing. I'm also looking for a small globe viewer. something that would take in a map and show a globe that can be turned by dragging the mouse.



povguild.jpg

I'm not sure if this would suit your needs or not, but I found this site not long ago and it has a bunch of cool map formats as well as the map-to-globe capabilities: https://www.maptoglobe.com/

[johnvanvliet]

Can Celestia convert Mercator to Plate-Carree?

no, it is just a solar system / space sim .

I have been trying to find anything similar to MMPS that will quickly re-project maps.

i think you are stuck with MMPS

[MollyJ]

Thank you Turambar, I have never seen that site before. I gave it a test and it worked beautifully. I'll post an animated gif from There tomorrow along with one I made with ImageMagick.