Jump to content

 
Photo

Projecting past 180 deg in Manifold?

- - - - -

  • Please log in to reply
2 replies to this topic

#1
woneil

woneil

    Will O'Neil

  • Validated Member
  • PipPipPipPip
  • 115 posts
  • Gender:Male
  • Location:Falls Church, Virginia
  • United States

Some GIS and mapping software I am familiar with can make maps that extend across the 180 deg meridian very simply from conventional -180 to +180 deg data sets. Is Manifold able to do this? I haven't been able to find out how. When I re-project such a drawing or surface with a center at, say, 165 deg, everything east of 180 deg comes out blank. Of course it is possible to take -180 to +180 deg data sets apart and put them back together as, say, 0 to +180 to -180 to 0 deg data sets, but I'd like to find a simpler way if I can, since I often have need of Pacific-oriented maps.

(Note: I also posted this question on the Manifold forum.)
Will O'Neil
Author and amateur cartographer

http://analysis.williamdoneil.com/w.d.oneil@pobox.com

#2
Nick Springer

Nick Springer

    CartoTalk Founder Emeritus

  • Moderator
  • PipPipPipPipPipPip
  • 939 posts
  • Gender:Male
  • Location:Crosswicks, NJ
  • Interests:Cartographic Design, Print Maps, Graphic Design, Web Development, Ultimate Frisbee
  • United States

I ran into this same problem in Manifold and also posted to the Manifold forum. THe short answer is: it can't do it (unless somethign has changed). It's definitely a limitation. It also has problems with any links that cross the 180 line (they end up drawing across the whole map).

Nick Springer

Director of Design and Web Applications: ALK Technologies Inc.
Owner: Springer Cartographics LLC


#3
Hans van der Maarel

Hans van der Maarel

    CartoTalk Editor-in-Chief

  • Admin
  • PipPipPipPipPipPipPip
  • 3,803 posts
  • Gender:Male
  • Location:The Netherlands
  • Interests:Cartography, GIS, history, popular science, music.
  • Netherlands

I did this with rasters and it sort of worked. A raster image that crosses the 180 degrees boundary gets drawn entirely on one side of the map. Not sure what the algorithm behind it is.
Hans van der Maarel - Cartotalk Editor
Red Geographics
Email: hans@redgeographics.com / Twitter: @redgeographics




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users

-->