(no subject)

Hi All

Thanks Dennis :) that does help and plot a negative slope.

I am just having some trouble with the plot as it seems to not be plotting along the lat and lons fully. Attached is the plot that the code produces, I think it might be something in the plot line, I have attached the code and output below.
Many thanks! :)

Kind Regards
Melissa

;*************************************************
; regline.ncl
;

;*************************************************
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"

begin
;************************************************
; Read in Precip Data.
;************************************************
 fili = "/mnt/nfs2/geog/ml382/melphd/regressionline/siczoutputprregline/pr_Amon_ACCESS1-0_historical_safrica_climDJF1.nc" ; data

 f = addfile (fili , "r") ; add file
 lat = f->lat ; get lat
 lon = f->lon ; get lon
 time = f->time ; get time
 level = f->z ; get level
 pr = f->pr
 pr1 = pr(:,0,:,:) ; get precip
 pr2 = pr(0,0,:,:) ; ignore level&time, just want lat, lon

 printVarSummary(pr2)

  locmax = local_max(pr2,False,0.)
   x=lon(locmax@xi) ; get lat/lon points of maxima
   y=lat(locmax@yi)
   z=locmax@maxval

  print(locmax)
  print(y)
  print(x)
  print(z)

   ; your data
     x = (/ 43.5, 37.5, 37.5, 51, 46.5,30, 22.5, 52.5, 28.5/)
     y = (/-26.25, -23.25, -20.25, -17.2, -14.25, -12.75 \
           ,-11.25, -11.25, -3.75/)

     ii = dim_pqsort_n(x,1,0) ; indices of ascending x
     print(ii+" "+x(ii)+" "+y(ii))
     print("========================")

     rc = regline(x(ii),y(ii))
     print(rc)

 ;************************************************
; Create an array to hold both the original data
; and the calculated regression line.
;************************************************
 data = new ( (/2,dimsizes(y(ii))/), typeof(y(ii)))
 data(0,:) = y(ii)
; y = mx+b
; m is the slope: rc returned from regline
; b is the y intercept: rc@yave attribute of rc returned from regline

 data(1,:) = rc*(x(ii)-rc@xave) + rc@yave

;************************************************
; plotting parameters
;************************************************
 wks = gsn_open_wks("X11","ACCESS1-0_regline") ; specifies a ps plot

 res = True ; plot mods desired
 ;res@gsnAddCyclic = False
 res@gsnMaximize = True ; maximize plot in frame
 res@xyMarkLineModes = (/"Markers","Lines"/) ; choose which have markers
 res@xyMarkers = 16 ; choose type of marker
 res@xyMarkerColor = "red" ; Marker color
 res@xyMarkerSizeF = 0.01 ; Marker size (default 0.01)
 res@xyDashPatterns = 1 ; solid line
 res@xyLineThicknesses = (/1,2/) ; set second line to 2

 res@tiMainString = "Regline" ; title

 plot2 = gsn_csm_xy (wks,pr2&lon,data,res) ; create plot
end

Variable: pr2
Type: float
Total Size: 2960 bytes
            740 values
Number of Dimensions: 2
Dimensions and sizes: [lat | 20] x [lon | 37]
Coordinates:
            lat: [-29.25..-0.75]
            lon: [ 0.. 54]
Number Of Attributes: 11
  z : 0
  valid_max : 0.001398626
  valid_min : -6.214417e-24
  time : 11
  date : 01/01/50
  title : pr
  name : pr
  source :
  _FillValue : 2e+20
  units :
  long_name : pr

Variable: locmax
Type: integer
Total Size: 4 bytes
            1 values
Number of Dimensions: 1
Dimensions and sizes: [1]
Coordinates:
Number Of Attributes: 3
  maxval : ( 104.526, 231.4876, 239.5204, 300.4584, 541.7598, 344.9508, 349.5831, 353.6486, 298.2738 )
  xi : ( 29, 25, 25, 34, 31, 20, 15, 35, 19 )
  yi : ( 2, 4, 6, 8, 10, 11, 12, 12, 17 )
(0) 9

Variable: y
Type: double
Total Size: 72 bytes
            9 values
Number of Dimensions: 1
Dimensions and sizes: [lat | 9]
Coordinates:
            lat: [-26.25..-3.75]
Number Of Attributes: 4
  axis : Y
  standard_name : latitude
  units : degrees_north
  long_name : latitude
(0) -26.25
(1) -23.25
(2) -20.25
(3) -17.25
(4) -14.25
(5) -12.75
(6) -11.25
(7) -11.25
(8) -3.75

Variable: x
Type: double
Total Size: 72 bytes
            9 values
Number of Dimensions: 1
Dimensions and sizes: [lon | 9]
Coordinates:
            lon: [43.5..28.5]
Number Of Attributes: 4
  axis : X
  standard_name : longitude
  units : degrees_east
  long_name : longitude
(0) 43.5
(1) 37.5
(2) 37.5
(3) 51
(4) 46.5
(5) 30
(6) 22.5
(7) 52.5
(8) 28.5

Variable: z
Type: float
Total Size: 36 bytes
            9 values
Number of Dimensions: 1
Dimensions and sizes: [9]
Coordinates:
(0) 104.526
(1) 231.4876
(2) 239.5204
(3) 300.4584
(4) 541.7598
(5) 344.9508
(6) 349.5831
(7) 353.6486
(8) 298.2738
(0) 6 22.5 -11.25
(1) 8 28.5 -3.75
(2) 5 30 -12.75
(3) 2 37.5 -20.25
(4) 1 37.5 -23.25
(5) 0 43.5 -26.25
(6) 4 46.5 -14.25
(7) 3 51 -17.2
(8) 7 52.5 -11.25
(0) ========================

Variable: rc
Type: double
Total Size: 8 bytes
            1 values
Number of Dimensions: 1
Dimensions and sizes: [1]
Coordinates:
Number Of Attributes: 7
  _FillValue : 9.969209968386869e+36
  yintercept : -6.582466643682366
  yave : -15.57777786254883
  xave : 38.83333333333334
  nptxy : 9
  rstd : 0.2353886391074344
  tval : -0.9840700740088305
(0) -0.2316389155072908

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