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

[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]

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.

[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.

[RobA]

Snargash-

I uploaded a video to youtube showing how I did this. Sorry for the lousy video quality, but the explanation should help.... when it is approved at ShowMeDo I'll provide a link to the better quality video.

http://www.youtube.com/watch?v=TEZYLxzwcUE

Here is the ShowMeDo Link. Still not as clear as I'd like because I inadvertently downsized it then unsized it but at least you can see the buttons better,
http://showmedo.com/videos/video?nam...omSeriesID=262

Just let it buffer before playing...

-Rob A>

[Snargash Moonclaw]

Wow! Thanks. The screen shots are too blurry to actually catch which buttons, but from the audio and the general positions of the cursor I should be able to work it out if/when I get to that stage. The scanned image shows all the poorly erased line, uneven pressure on the correct ones, pencil waver and everything else - esp the smudging on a rather old peice of paper. . . I may well do a trace and rescan a cleaner image as well as adjusting the circumpolar coastlines toward the equator in some spots. Using an earth overlay in G.Projector gives a really good comparison in terms of latitudes. As I said elsewhere the polar circles and tropics are smaller/narrower due to a reduced axial tilt - my eyeball nailed the lines directly at 15 and 75 degrees I'm happy to learn! Even so some areas could stand being brought down a little. The planet's extremely warm at present with no icecaps, only glaciers in thepolar regions. (It circles binary stars orbiting their midpoint minimally slower than the planet's orbit - creates a 40,000 year glacial cycle when the smaller is eclipsed by the larger for 10 thousand and visible for 30) Anyway, this is giving me a good training projext aed in better depth ct to focus on learning to use Gimp. Do you reccommend any books on the program? I can usually find out what I'm wanting much faster and in greater depth using a good physical manual than in electronic documsntation/help files.

BTW, how did you pull the sphere into GoogleEarth format? That's an awesomne way to share it with players. I'm not sure how much Sketchup will let me play with it - I made a brief stab but it kept telling me to zoom in more. Still, it looks like I can attach objects to the sphere from it, I just don't know how much scale I have to play with at the larger end. . .

[RobA]

Under My Places, just go "Add-> Image Overlay"

Browse for a local equirectangular projection.

Under the Location Tab set North=90N, SOuth=90S, West=180W and East=180E.

Once you click OK, just right click and save it as a kmz file. It will embed the image in the file for you.

Oh, I also added the ShowMeDo link.

-Rob A>

[Snargash Moonclaw]

Thanks - had no trouble doing so - cleaned up the image a bit and played with getting it into a sphere and sent the kmz from it to a couple of friends. . .

[SeerBlue]

I am not sure how accurate this info is, but I have read that if you rename a .kmz file to a .zip file you can "unzip" it with 7 zip. If it is true it may give you access to your image, but that only helps if google earth saved it in its reprojected size/shape/projection, and did not just save coordinates to pin the corners to for on the fly reprojection..
SeerBlue

edit, a quick check shows it just stores the bounding box coordinates fo ron the fly reprojection, at least with my simple test. You can rename the file as a zip and extract the image file though.

[ninguid]

Hi all,
Not sure if this is handy or not but it is a rotating video of the map projected onto a sphere.
I used a similiar method when creating a 3D globe that I recently posted about in the finished works forum.

There is a bit of a seam on the backside of the globe where the ends of the image meet. Normaly this could be removed by making a 3D CAD model of the globe, but rendering an image/decal onto a sphere takes less time.

Angle of rotation could be set to any value. The frame rate could be varied to allow the video to rotate a certain number of degrees per frame.
This should be a 10 second video with 10 frames per second.

Zip file is 2Mb