Atmospheric halo effect around mollweide projection of earth

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06-20-2011 03:04 PM
GerickeCook
New Contributor III
Looking for a tool or cartographic trick to create a halo effect around an image of the earth that I'm using in a global pathways map. The projection is Mollweide, because I want something of an "earth from space" look but still capturing all the continents. Therefore I cannot use ArcGlobe or some other 3D mapping program.

I've tried buffering an envelope of the earth (error due to exceeding max bnd), graduated fills of ellipses with custom color ramps, large stack of line widths to simulate buffer/halo, etc. Nothing I've tried so far achieves the effect I want. I've searched ArcGIS Online and arcscripts but haven't found anything.

Any ideas?
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6 Replies
MelitaKennedy
Esri Notable Contributor
I'm not strong on cartographic effects! The buffer might work, but what I would do to avoid any valid/invalid envelope issues is to remove the coordinate system/spatial reference information. Then you should be able to just display the buffered polygon in ArcMap underneath the real data. Depending on how you add that layer to ArcMap, you may get a 'unknown spatial reference, cannot reproject' warning, but you can ignore it.

Melita
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SimonKettle
Regular Contributor
Maybe you can manipulate the process discussed on the Mapping Centre site?

See: http://mappingcenter.esri.com/index.cfm?fa=ask.answers&q=1381 and http://mappingcenter.esri.com/index.cfm?fa=ask.answers&q=1367
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GregoryElwood
New Contributor II
A non-GIS solution may be in order.

Mixing GIS imagery with any number of available graphics and/or effects software may allow for more control of the appearance of the halo and, maybe, involve less time to get it just right, although at an increased cost for the additional resources.

I recommend investigating Adobe After Effects, or perhaps even Autodesk Maya. Lots of fun. TONS of learning curve. Perfect imagery.

Whats that old saying? Quality, price, speed...pick any two!

Not that helpful, I know. But it's good to know about the universe of computer graphics outside of GIS.

Gregory
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JimW1
by
Occasional Contributor II
Friday Afternoon Challenge Accepted

This is a variation on a technique I use to make another projection have the halo effect. See Attached.

It needs about 20 minutes more of fine-tuning but this isn't my map :)

I'll share my technique if this is what you're looking to do.

99.5% ArcMap
0.5% MS-Paint

The BING raster screws up the export (hence the MS-Paint) but if you have vector data it works great. See Second Attached (100% ArcMap) - had to make sure it worked in mollweide and it's only a 150dpi jpeg.
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DarrenWiens2
MVP Honored Contributor
I'll expand on what I did, since Jim is being so darn cryptic :p

1.) Display imagery with transparent background (the default)
2.) Draw an ellipse in layout that is larger than the imagery
3.) In the ellipse properties -> Choose Symbol... -> Edit Symbol... -> Type = Gradient Fill Symbol
4.) Choose a color ramp that fades to black. 'OK' your way back to the layout
5.) Send the ellipse back so you can see it and the imagery
6.) Draw a big black rectangle and send it to the back

100% ArcMap
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JimW1
by
Occasional Contributor II
I'll expand on what I did, since Jim is being so darn cryptic :p

1.) Display imagery with transparent background (the default)
2.) Draw an ellipse in layout that is larger than the imagery
3.) In the ellipse properties -> Choose Symbol... -> Edit Symbol... -> Type = Gradient Fill Symbol
4.) Choose a color ramp that fades to black. 'OK' your way back to the layout
5.) Send the ellipse back so you can see it and the imagery
6.) Draw a big black rectangle and send it to the back

100% ArcMap



Oh I wrote it all out in steps and then the forum crashed and was too lazy to re-write :)
If anyone stumbles accross this post then Darren is bang on with his process steps. The only thing I would add is to anchor everything to the centre point as it makes sizing easier with circles and ellipses.


I use the variant of this method to give an eye-glass look to circular inset maps. It's a shame they haven't updated the transparency export capabilities in 10 or added something as simple as feathering edges.

This is the kind of thread I hope the Cartography forum expands into where we can really get down to making some good looking maps. It's a shame that most of us likely do not have IP or publishing rights on our own work otherwise we could post some examples of cool tricks.
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