# Re: [ferret_users] Outlining grid boxes

```jagadish karmacharya a écrit :
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```Dear all,

```
I wanted to outline each grid box of a grided data. For this, I used the method suggested by Jaison ( http://www.pmel.noaa.gov/maillists/tmap/ferret_users/fu_2004/msg00774.html) but got the attached plot. (grid_center....) Seems like the corner of the overlay box/rectangle lay over the grid center (rather than at the edge as I wanted). How can I overlay the box so as to match undrlaying grid?
```
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Also, some time ago I made plot (grid.gif) with marker at grid center but now forgot how i did that. Can any one suggest?
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Regards

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```Hi,
Here is an example of what can be made using the polygon command.
Patrick

```

```!========================================================
use levitus_climatology

!========================================================
let ME_VAR=temp[k=1]
let ME_VAR0=ysequence(ME_VAR)

!========================================================
! build vector boundaries
let XLO = YSEQUENCE(X[GX=ME_VAR]*Y[GY=ME_VAR]*0+XBOXLO[GX=ME_VAR])
let XHI = YSEQUENCE(X[GX=ME_VAR]*Y[GY=ME_VAR]*0+XBOXHI[GX=ME_VAR])
let YHI = YSEQUENCE(X[GX=ME_VAR]*Y[GY=ME_VAR]*0+YBOXHI[GY=ME_VAR])
let YLO = YSEQUENCE(X[GX=ME_VAR]*Y[GY=ME_VAR]*0+YBOXLO[GY=ME_VAR])

!========================================================
!   (1) x-------x (2)
!       |       |
!       |   +   |
!       |       |
!   (4) x-------x (3)
!

! build a variable with longitude boundaries
let BOUNDS_LON_0 = YSEQUENCE(X[GX=ME_VAR]*Y[GY=ME_VAR]*0)+I[I=1:4]
let BOUNDS_LON_1 = IF BOUNDS_LON_0 EQ 1 THEN XLO ELSE BOUNDS_LON_0
let BOUNDS_LON_2 = IF BOUNDS_LON_0 EQ 2 THEN XHI ELSE BOUNDS_LON_1
let BOUNDS_LON_3 = IF BOUNDS_LON_0 EQ 3 THEN XHI ELSE BOUNDS_LON_2
let BOUNDS_LON_4 = IF BOUNDS_LON_0 EQ 4 THEN XLO ELSE BOUNDS_LON_3
set variable/title="Longitude" BOUNDS_LON_4

! build a variable with latitude boundaries
let BOUNDS_LAT_0 = YSEQUENCE(X[GX=ME_VAR]*Y[GY=ME_VAR]*0)+I[I=1:4]
let BOUNDS_LAT_1 = IF BOUNDS_LAT_0 EQ 1 THEN YHI ELSE BOUNDS_LAT_0
let BOUNDS_LAT_2 = IF BOUNDS_LAT_0 EQ 2 THEN YHI ELSE BOUNDS_LAT_1
let BOUNDS_LAT_3 = IF BOUNDS_LAT_0 EQ 3 THEN YLO ELSE BOUNDS_LAT_2
let BOUNDS_LAT_4 = IF BOUNDS_LAT_0 EQ 4 THEN YLO ELSE BOUNDS_LAT_3
set variable/title="Latitude" BOUNDS_LAT_4

!========================================================
polygon/set_up/fill/line/hlim=100:300/vlim=0:60/title="maps with polygons"/lev=20 BOUNDS_LON_4, BOUNDS_LAT_4, ME_VAR0
ppl xfor (I7,''LONE'')          ! set longitude axis labels
ppl yfor (I7,''LAT'')           ! set latitude axis labels
ppl fillpol/line/fill

go land

! Note that /modulo qualifier does not exist for polygon command
```