# [ncl-talk] Getting location and dates of a point(s) that satisfy certain conditions

Lyndz olagueralyndonmark429 at gmail.com
Fri Apr 16 02:37:27 MDT 2021

Dear NCL-experts,

*[1] Details*
I have three variables dpdx, dpdy, and px2py2 with the following dimensions
and sizes:
*Dimensions and sizes: [time | 124] x [lat | 73] x [lon | 144]*
These variables were derived using spherical harmonics.

*[2] Problem and what I have done so far*

(a) I want to get the dates when any gridpoint in a specified domain
satisfies the following conditions:
dpdx = 0 *.and.* dpdy = 0 *.and. *px2py2 *.lt.* 0

(b) get the coordinates of these points, if possible.

I have the following lines in my script:

latS = 5.0

latN = 30.0

lonL = 120.0

lonR = 160.0

dpdx_region=dpdx(:,{latS:latN},{lonL:lonR})

dpdx_region=dpdy(:,{latS:latN},{lonL:lonR})

px2py2_region=px2py2(:,{latS:latN},{lonL:lonR})

I am stuck here. I dont know what index I should use to get the dates and
how to get their coordinates.

dpdx_thres  = dim_num_n((dpdx_region .eq. 0),(/1,2/))

dpdy_thres  = dim_num_n((dpdy_region .eq. 0),(/1,2/))

px2py2_thres  = dim_num_n((px2py2_region .lt. 0),(/1,2/))

n_thres  = ind(dpdx_thres .gt. 0 .and. dpdy_thres .gt. 0 .and.
px2py2_thres .gt. 0 ) ;time indices but i'm not sure if this is correct!

print(n_thres)

print("=====")

if(ismissing(nt_thres(0))) then

print("++++++++++++++")

print(" NO values exceed threshold="+threshold)

print("++++++++++++++")

exit

end if

I am attaching my script.

I'll appreciate any help on this!

Sincerely,

*Lyndz*
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