poly-vector in hammer projection

[Boyin Huang <huang_boyin@xxxxxxxxx>]

Dear Ferreters:

I used demo script for poly-vector plot, which is
originally in mp_stereographic_north projection.

After I changed it into hammer projection, all vectors
were moved to one longitude, and longitude and
latitude lines were also shifted thogh the shape looks
OK.

What is wrong with the code attached in e2.jnl

In a simpler case, I tried to plot vectors only using
different spatial region, an error message was given
as follows:
inconsistent sizes of data regions: Y axis
ERIDIAN_ANGLE has 546 points (J=001:546)
          expression has 600 points (J=001:600)

Can we simply ignore the third argument when calling
polygon?

The code is attached in e3.jnl

------------------------------------
!e2.jnl:
USE coads_climatology

SET REGION/X=131:181/Y=21:61/L=5
!LET mp_central_meridian = (131+181)/2
!LET mp_standard_parallel = (60+20)/2

!GO mp_stereographic_north  `mp_central_meridian`
`mp_standard_parallel`
go mp_hammer

!SET GRID uwnd
GO mp_grid uwnd
GO mp_grid vwnd
GO mp_grid slp
GO mp_aspect

FILL/NOAXIS/NOKEY/PAL=inverse_grayscale/TITLE="Winds
Colored by Pressure" slp, x_page,y_page
GO mp_fland 20 black

LET x_vec = X[GX=uwnd,X=131:181] +
0*Y[GY=uwnd,Y=21:61]
LET y_vec = 0*X[GX=uwnd,X=131:181] +
Y[GY=uwnd,Y=21:61]
LET u_vec = uwnd[X=131:181,Y=21:61,L=5]
LET v_vec = vwnd[X=131:181,Y=21:61,L=5]

GO mp_poly_vectors x_vec y_vec u_vec v_vec 3 "arrow"

LET press = YSEQUENCE(slp[X=131:181,Y=21:61,L=5])
POLYGON/OVER/NOAX/NOLAB/KEY/LINE/PAL=rainbow
mp_x_arrow, mp_y_arrow, press

GO mp_graticule 131 181 12.5 21 61 10 1

--------------------------------------------------
!e3.jnl

USE coads_climatology

SET REGION/X=121:181/Y=21:61/L=1

go mp_hammer
GO mp_grid uwnd
GO mp_grid vwnd
GO mp_grid slp
GO mp_aspect

LET x_vec = X[GX=uwnd,X=121:181] +
0*Y[GY=uwnd,Y=21:61]
LET y_vec = 0*X[GX=uwnd,X=121:181] +
Y[GY=uwnd,Y=21:61]
LET u_vec = uwnd[X=121:181,Y=21:61,L=1]
LET v_vec = vwnd[X=121:181,Y=21:61,L=1]

GO poly_vectors x_vec y_vec u_vec v_vec 5 "arrow"

LET press = YSEQUENCE(slp[X=121:181,Y=21:61,L=1])
POLYGON/OVER/NOAX/NOLAB/KEY/LINE/PAL=rainbow
mp_x_arrow, mp_y_arrow, press

poly_arrow_key "winds", "5 m/s"


CAN VAR/ALL
CAN REGION






=====
Boyin Huang
The Center for Research on the Changing Earth System (CRCES)
10211 Wincopin Circle, Suite 240
Columbia, Maryland 21044
Tel. 410-992-5300/19 (O), 410-461-9339(H) 
Fax. 410-992-5944, Email. byh@crces.org 
http://byh.crces.org


		
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