Re: MetApps ShapefileAdapter

• To: "Luke A. Catania (TEC)" <lcatania@xxxxxxxxxxxx>
• Subject: Re: MetApps ShapefileAdapter
• From: Bill Hibbard <hibbard@xxxxxxxxxxxxxxxxx>
• Date: Fri, 24 May 2002 04:58:05 -0500

"Luke A. Catania (TEC)" wrote:
> 
> Is there a way to use a map projection with VisAD?   If so  there example
> code?? After using the DisplayImplJ3D, I was able to get the map of the
> world shape file displayed, but it does not look correct because of the lack
> of a map projection.

That's the role of the visad.CoordinateSystem class. Map
projections (including satellite navigation, etc) are
defined by subclasses of CoordinateSystem. So if your data
have MathType ((row, column) -> value) you can give the
RealTuple (row, column) a CoordinateSystem with reference
(latitude, longitude).

You can also do this on the display side, defining three
new instances of DisplayRealType, and using them in a
DisplayTupleType with a CoordinateSystem with reference
(XAxis, YAXis, ZAxis). Then create ScalarMaps to your
new DisplayRealTypes. If you look in visad/Display.java
you'll see this is how Display spherical coordinates:

  (Latitude, Longitude, Radius)

are defined. Unidata's Metapps package uses this technique
to define a variety of Display side map projections for
Lambert conformal, etc.

Cheers,
Bill

• References:
  • RE: MetApps ShapefileAdapter
    • From: Luke A. Catania (TEC)