Hi Muraleedharan,
Here you can define a mask which is 1 inside the region and missing
everywhere else. Here's documentation about masking:
http://ferret.pmel.noaa.gov/Ferret/documentation/users-guide/variables-xpressions/XPRESSIONS#_VPID_181
The PT_IN_POLY function would let you define a mask which is 1
inside the region and missing everywhere else
yes? show func pt_in_poly
PT_IN_POLY(A,XVERT,YVERT)
Return -1 outside, 0 if on edge, 1 if inside polygon
A: Variable on the XY grid and region to be tested
XVERT: X-coordinates of vertices of polygon
YVERT: Y-coordinates of vertices of polygon
yes? let xpts = {x1,x2,x2,x1}
yes? let ypts = {y1,y1,y2,y2,y1}
yes? let mask = ifv pt_in_poly(var, xpts, ypts) GE 0 then 1 !
or GT 0, your choice
yes? let masked_var = var* mask
! check the region and mask graphically
yes? shade var
yes? plot/over/nolab/vs/line xpts, ypts
yes? shade/over/nolab masked_var
yes? list masked_var[x=@ave,y=@ave]
On 4/23/2016 11:20 PM, Murali Kallungal
wrote:
Hi friends
I am working in a region where numerous islands and zig-zag
coastline.
I would like to average data over a polygon or diamond
shape (x1y1,x2y1,x2y2,x1y2,x1y1)
How can I do this in ferret
Regards
Muraleedharan
--
-------------------------------
Muraleedharan
K.R
-------------------------------
Scientist
National Institute of
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