Software that meets specific technical needs in manipuation of projection and display

[Snargash Moonclaw]

http://www.jhendor.de/tutorials/cc2-ft.pdf shows how Ralf over at ProFantasy did something similar years ago. Steps 1 through 4 should be applicable.

There are better bits of software out these days that some of the folks hereabouts prefer such as G.Projector or Flex-projector.

Thanks for the input. Unfortunately the tutorial doesn't really offer any info on converting projections - while he started with a polar projection in CC2 and ended with the type that I would like (to go back and forth between) that seems to be more of a side effect of whatever he was seeking to accomplish in converting the data format from CC2's to FT. I didn't really comprehend most of it as I have never used either program nor any of the other utilities he utilized during the intermediate stages.

I am hoping to locate a single program that will simply handle both types of projections from a single initial map. (Which is why I'm wondering if CC2 or 3 would do that - if the change in projection had been all that he was seeking did he even need any second program?) Because of the unusual way the two continents are situated over and surrounding the two poles I have to start with the polar projections when mapping the entire globe. I simply can't perceive the coastlines and other features clearly and properly in my head in another type of projection to draw them broken apart in pieces or spread out linearly. Even having the initial polar projections I still find it extremely difficult to attempt to map the more extreme parallels by hand in any sort of rectangular presentation.

The two programs you mentioned looked promising, but after downloading and running both I found that neither will deal with polar projections in any fashion (starting or ending) - they work solely with rectangular representations of an entire globe centered on the equator which adjust for the distortion that flat Cartesian mapping produces as you approach the poles. I may have use for them later, but sadly they don't do what I'm needing here since they start and end with variations on the sort of projections I'm unable to produce.

HF, PW,
AOK
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[waldronate]

Using ReprojectImage I got the first two images shown below and assembled them in Photoshop to get the third image (approximately the equirectangular projection needed for the other reprojection programs). Putting that image into FT I got the last image, which shows that world on a globe.

Note that this was a quick operation and I didn't fiddle with the parameters to reprojectimage to get a perfect layout. Some things don't perfectly line up along the equator and the lines aren't perfectly straight. The curved lines are caused by not getting the reprojectimage parameters correct. Things not lining up correctly may be partly due to that problem but may also be partly due to source material.

I tried to get the other images to line up but I couldn't find a good location to do that.

[Snargash Moonclaw]

That globe totally rocks! It also tells me that I need to make some changes to my coastlines to get what I want in this perspective (the projection is very informative) - bring them a little further down from the poles and carry the southern continent's equitorial coastline eastward more before turning it south as the concept for the equatorial (The Suntrack) Sea is a longer band of water between the two continents. I would love a program that would create this projection from the two polar ones and allow me to make the changes I mentioned directly on the global projection then convert the modified file again back to polar or some other projection. I get the feeling that CC3 is the only likely candidate in that regard but I don't know if that can even do it.

As far as my attempting to repeat the process you used, what is ReprojectImage, where is it available and is it free/share/or market ware ? Will GIMP do the photoshopped step? While I'd have to purchase FT, even being able to create an acurate equirectilinear projection would be very useful and the two projector progams you mentioned earlier can take care of a lot of the distortion. I knew I'd have mapping problems when I first envisioned the planet but its unusual geography creates some desirable effects upon the game setting.

[waldronate]

ReprojectImage is a program I wrote long ago to get general map projections into the equirectangular/Plate Caree projection. It's the tool that Ralf used in his tutorial to reproject his image to get it into FT and can be found at http://www.ridgenet.net/~jslayton/ReprojectImage.zip if you'd like to fiddle with it. It's free to use.

GIMP or any other image manipulation tool will work well for manipulating the images. All I did in Photoshop was up the contrast of the base images and stitch together the two half images.

FT isn't a required part of the activity, it was just convenient way to do the globe projection. There are many other ways to do that part, including Wilbur (http://www.ridgenet.net/~jslayton/software.html). Please note that I am in no way attempting to discourage you from buying a copy of FT.

CC3 doesn't do projections.

I would recommend working on the equirectangular projection if you can because going back and forth between projections causes some pretty significant distortions of the image near the pole.

[Snargash Moonclaw]

Hmm. Will anything permit me to work on this in the way I was describing? I don't really know what the different programs will do. I have GIMP but really don't know how to use it - basically I've just resized pictures with it - I know nothing at all about graphic software. I'm simply trying to find something which will let me perceive the mapping data (image) in different ways and edit it in them. i.e. - both globes (the one RobA did in GIMP and yours) only show a portion - what would let me move the globe around (as if I were in Worldwind or GoogleEarth)? I don't understand your last recommendation - the equirectangular projections are extremely distorted around the edges - I don't see how I could work in them if I were doing anything to the coastlines beyond about the 45th parallels. After doing some referencing those coastlines may not be as bad as I first thought seeing the globe (but I need to see them completely in that form) - the planet's axial tilt is less than Earth creating ant/arctic circles at about 73.5 degrees and tropics at about 16.5 rather than 66.6 and 23.4 - those are the red lines - not specifically calculated - placed on the polar projections as eyeball approximates of where I want them.

HF, PW,
AOK

CC3 doesn't do projections.

I would recommend working on the equirectangular projection if you can because going back and forth between projections causes some pretty significant distortions of the image near the pole.

[waldronate]

Any flat representation of a sphere will have distortions when you put it on paper; that's the nature of map projections. I do not know a good drawing tool that works on spheres directly. A 3D modelling tool would likely have this capability but I'm not much up on modern 3D tools.

The image overlay painting tools in FT are laughably primitive and prone to brush shape distortion but they do let you paint on projections other than equirectangular, including orthographic (the sphere one).

[Snargash Moonclaw]

Any flat representation of a sphere will have distortions when you put it on paper; that's the nature of map projections. I do not know a good drawing tool that works on spheres directly. A 3D modelling tool would likely have this capability but I'm not much up on modern 3D tools.

The image overlay painting tools in FT are laughably primitive and prone to brush shape distortion but they do let you paint on projections other than equirectangular, including orthographic (the sphere one).

Woot - G.Projector will put the equirectangular image into a sphere (Vertical Perspective) which I can rotate in any direction by specifying the lat and long to center on! Now I'm finally getting somewhere! Both sphere's show that my approximations of the islands along the equators of the two polar projections don't line up - This should be fixable on the equirectangular projection in GIMP which I can then look at in G.P. However, any changes I might try to make to the coastlines further out would need to be done on the sphere in order to see what I'm actually doing.

[RobA]

Hmm. Will anything permit me to work on this in the way I was describing? I don't really know what the different programs will do. I have GIMP but really don't know how to use it - basically I've just resized pictures with it - I know nothing at all about graphic software. I'm simply trying to find something which will let me perceive the mapping data (image) in different ways and edit it in them. i.e. - both globes (the one RobA did in GIMP and yours) only show a portion - what would let me move the globe around (as if I were in Worldwind or GoogleEarth)? I don't understand your last recommendation - the equirectangular projections are extremely distorted around the edges - I don't see how I could work in them if I were doing anything to the coastlines beyond about the 45th parallels. After doing some referencing those coastlines may not be as bad as I first thought seeing the globe (but I need to see them completely in that form) - the planet's axial tilt is less than Earth creating ant/arctic circles at about 73.5 degrees and tropics at about 16.5 rather than 66.6 and 23.4 - those are the red lines - not specifically calculated - placed on the polar projections as eyeball approximates of where I want them.

HF, PW,
AOK

I'm not sure if I know what you want.... do you want to edit on a sphere? Even the ones you mention (like googleearth) assume a 1:1 pixel to degree lat/long ratio. in source images you map on them.

Most of the software will take an equirectangular projection (2:1) and plot it on a sphere, but as you noted, there is a lot of distortion at the poles.

The programs previously identified (flexprojector, and something else) also start with 2:1 images.

The problem is that anytime you convert raster images (pixel based) between coordinate system you will get serious distortion...and I am not sure there is any vector software that will work in multiple projections.

Attached is the equirectangular projection pulled into googleearth format. Just open the zip, extract the kmz file and open it in googleearth. That works for viewing, but I don't see how you could "zoom in an edit" and then bring it back...

-Rob A>

[Snargash Moonclaw]

NASA's G.Projector is putting it into a sphere - don't know if I can move a given perspective into GIMP, edit it and then have G.P flatten it back out since I wouldn't really be working on the whole thing - just a visual portion.

THe GoogleEarth file is awesome - very useful. Will Google Sketchup work with these file types? have copy, haven't used it. . . The biggest thing I need to do is correct the islands on the equator and get the two halves of them lined up. - this at least can be done readily on the equirectangular projections.

I'm not sure if I know what you want.... do you want to edit on a sphere? Even the ones you mention (like googleearth) assume a 1:1 pixel to degree lat/long ratio. in source images you map on them.

Most of the software will take an equirectangular projection (2:1) and plot it on a sphere, but as you noted, there is a lot of distortion at the poles.

The programs previously identified (flexprojector, and something else) also start with 2:1 images.

The problem is that anytime you convert raster images (pixel based) between coordinate system you will get serious distortion...and I am not sure there is any vector software that will work in multiple projections.

Attached is the equirectangular projection pulled into googleearth format. Just open the zip, extract the kmz file and open it in googleearth. That works for viewing, but I don't see how you could "zoom in an edit" and then bring it back...

-Rob A>

[Snargash Moonclaw]

Now how did you pull it into GoogleEarth format - I can't see KMZ as a file type GIMP will "save as". Now the biggest questions for me come down to using GIMP - first finding out what actually can be done, particularly cleaning up this image in general to get rid of all the smudges, poorly erased pencil, etc. and just leave crisp lines. I did a quick edit to redraw the southern part of the islands on the equator then filled in a slight gray so it wasn't a glaring white patch where I dodged out the original lines. . .

Thanks again both of you for all the help - I'm finally actually getting somewhere with this. I would like to know how you got the polar projections into an equirectangular one - that way if I hand draw a new version (I'm thinking it may be easier/better to trace the parts I actually want from the original and rescan. . .) I can repeat it from the new polar projections.