[gradsusr] xy2gr bug?

Mon Jun 19 12:35:27 EDT 2017

Hey, GrADS list.

I'm getting an error with xy2gr - it's duplicating the results of xy2w but
only under specific circumstances. I'm using a Cartesian domain that's not
georeferenced (km from the origin as opposed to lat/lon on the planet). The
two functions give similar results up to a point. To wit:

Position = 5.15564 2.55131 1 0

ga-> q xy2gr 5.15564 2.55131

Xdim = 288.285  Ydim = -1179.48

ga-> q xy2w 5.15564 2.55131 

Lon = 3862.26  Lat = -1179.48

ga-> q xy2gr 5.15564 1.55131

Xdim = 288.285  Ydim = -1579.48

ga-> q xy2gr 5.15564 3.55131

Xdim = 288.285  Ydim = 74.3479

ga-> q xy2gr 5.15564 2.55131

Xdim = 288.285  Ydim = -1179.48

ga-> q xy2gr 5.15564 2.65131

Xdim = 288.285  Ydim = -1139.48

ga-> q xy2gr 5.15564 2.75131

Xdim = 288.285  Ydim = -1099.48

ga-> q xy2gr 5.15564 2.85131

Xdim = 288.285  Ydim = -1059.48

ga-> q xy2gr 5.15564 2.95131

Xdim = 288.285  Ydim = -1019.48

ga-> q xy2gr 5.15564 3.05131

Xdim = 288.285  Ydim = 68.7923

ga-> q xy2gr 5.15564 3      

Xdim = 288.285  Ydim = -1000

ga-> q xy2gr 5.15564 3.01

Xdim = 288.285  Ydim = 68.3333

ga-> q xy2w 5.15564 3.01 

Lon = 3862.26  Lat = -996

ga-> q xy2w 5.15564 3.00

Lon = 3862.26  Lat = -1000

The takeaway here is that when the position moves above -1000 "latitude,"
then xy2gr is giving me the y-position grid index. Below that, then it's the
"world" coordinate. I don't think the 3 means anything, here (just a guess).

Operator-error goof or bug?

~Dave

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