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Re: Bug in LambertAzimuthalEqualArea?



On 3/16/2011 7:18 PM, Robert B. Schmunk wrote:
John,

Between NJ 4.0.49 and 4.2.21, a bug seems to have crept into the
class for projecting data on a Lambert Azimuthal Equal Area grid.
I am wondering if this resulted from the "earth_radius attribute
on grid_mapping variable must be in meters" item in the change
history under version 4.1.15.

The problem that I'm seeing is that in an old copy of Panoply
which uses NJ 4.0.49, data on an LAEA grid are plotted as one
expects. But with the same data in a newer Panoply which uses
NJ 4.2.21, I find that the result returned by the latLonToProj
method needs to be scaled by a factor of 1000 if the data are
to be plotted correctly. (Presumably the projToLatLon method is
also off by a factor of 1000, in the other direction, although
I haven't tested that yet.) The LambertAzimuthalEqualArea object
is being obtained by calling getProjection() on the variable's
coordinate system and is not constructed from scratch.

The dataset I am working with, and which seems to be tagged
correctly, is located at
http://www.giss.nasa.gov/staff/rschmunk/open/azim_equal_area.nc
and includes some weather radar data for the United States.

rbs



--
Robert B. Schmunk, address@hidden
NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025

hi robert:

im not sure whats going on. the latest version of toolsui is displaying that file correctly.

are you opening the file as a GridDataset or some other way?

john