NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.
Current content can be found at unidata.ucar.edu.
To learn about what's going on, see About the Archive Site.
NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.
Current content can be found at unidata.ucar.edu.
To learn about what's going on, see About the Archive Site.
Hi John, > a beginner....i'm struggling with trying to understand how to plot a > coastline. i have sets of points forming line segments but can't see how > to use the visad data set types to connect the dots. i'm sure the examples > are there - but so far i haven't been able to find them. > > do i use the IrregularSet class? what to i do to implement? code snippets > welcome & appreciated..... The Rivers.java program in visad/examples shows the basic idea. You construct a UnionSet of a collection of Gridded2DSets, each with manifold dimension = 1. Each of the Gridded@DSets with manifold dimension = 1 is a sequence of points rendered as a continuous line (assuming the RealTypes components of the SetType are mapped to spatial DisplayRealTypes like XAxis and YAxis). The UnionSet is rendered as the disjoint union of these continuous lines (i.e., the pen lifts between Gridded2DSets). Also check out the SatDisplay program in visad/examples, which uses the visad.data.mcidas.BaseMapAdapter class to read McIDAS map files (usually named OUTL*) into UnionSets. These are overlaid onto satellite images. > Also, i've got a set of Quikscat wind speeds at irregular points in a > scalar and am about to write an objective analysis class to fill in the > holes so i can isocontour. i see hints of grid interpolation methods but > still find it hard to understand how to implement (i'm not that familiar > with how the pieces fit together) - so find myself resorting to custom code > to keep my spirits up. suggestions welcome here too! The easiest way to do this is to put your wind speeds into a FlatField whose domain Set is an Irregular2DSet that defines the locations of the wind speeds. If you map the domain RealTypes to spatial DisplayRealTypes and map wind speed to Display.IsoContour, then the VisAD display logic will render contour lines based on the irregular topology. This will allow you to skip the explicit objective analysis (which would of course interpolate your wind speeds to a Gridded2DSet). VisAD supports contouring algorithm for both gridded and irregular sampling topologies (and provides hooks for people to define their own contouring algorithms). > having fun, Glad to hear it. Please let me know if you have further questions. Cheers, Bill ---------------------------------------------------------- Bill Hibbard, SSEC, 1225 W. Dayton St., Madison, WI 53706 hibbard@xxxxxxxxxxxxxxxxx 608-263-4427 fax: 608-263-6738 http://www.ssec.wisc.edu/~billh/vis.html
visad archives: