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Re: [ferret_users] Outlining grid boxes

Thanks Ansley. I repeated your step 1 for the same data and it worked fine. But when I did the same carefully for my data there is always some shift in graticule over lay and edges of grid cells. Could it be due to the fact that grid cell edge value have 2 decimil values.

yes? list xboxlo[gx=temp]
             VARIABLE : XBOXLO
                        axis LONGITUDE12_107
             FILENAME : dhmad_blTam.nc
             SUBSET   : 96 points (LONGITUDE)
 74.56E /  1:  74.45
 74.78E /  2:  74.67
yes? list yboxlo[gy=temp]
             VARIABLE : YBOXLO
                        axis LATITUDE4_84
             FILENAME : dhmad_blTam.nc
             SUBSET   : 81 points (LATITUDE)
 33.36N / 81:  33.25
 33.14N / 80:  33.03

I found similar problem with gridxy.jnl and xgridlines.jnl script (I haven't tried other in the list)


--- On Fri, 10/30/09, Ansley Manke <Ansley.B.Manke@xxxxxxxx> wrote:

From: Ansley Manke <Ansley.B.Manke@xxxxxxxx>
Subject: Re: [ferret_users] Outlining grid boxes
To: "jagadish karmacharya" <j_karmacharya@xxxxxxxxx>
Cc: oar.pmel.ferret_users@xxxxxxxx
Date: Friday, October 30, 2009, 9:54 AM

Hi all,
I'd have one more idea and also some existing scripts -

1) If you have a regularly-spaced grid, you should also be able to use the /GRATICULE qualifier on the plot command itself, if you are careful to put the tic marks of the plot axes at the edges of grid cells:
yes? use etopo60

yes? ! Check the grid-cell edge values. Here they are at each degree.
yes? list/i=1:5 xboxlo[gx=rose]
yes? list/y=1:5 yboxlo[gy=rose]

yes? ! Use PPL XAXIS and PPL YAXIS to put the tic marks at each degree
yes? ! use /GRATICULE to draw line at each tic

yes? shade/set/x=1:20/y=-20:0/GRATICULE rose
yes? ppl xaxis 1,20,1
yes? ppl yaxis -20,0,1
yes? ppl shade
The graticule lines can be set to other colors and styles - see the documentation.

2) There are a few existing scripts to do this job.  The unix command Fgo to search for scripts containing the word "grid" (I removed a few from this listing that aren't relevant)

> Fgo grid
* * * * * * * * in /home/porter/tmap/ferret/x86_64-linux/go
gridlines.jnl: plot over the grid of a plot
gridxt.jnl: create an overlay of IL graticule lines to show the grid points
gridxy.jnl: create an overlay of IJ graticule lines to show the grid points
gridxz.jnl: create an overlay of IK graticule lines to show the grid points
gridyt.jnl: create an overlay of JL graticule lines to show the grid points
gridyz.jnl: create an overlay of JK graticule lines to show the grid points
gridzt.jnl: create an overlay of KL graticule lines to show the grid points
polar_grid_fancy.jnl: overlay "fancy" radial logitude and curved latitude lines
polar_grid.jnl: overlay "quick" radial logitude and curved latitude lines
tgridlines.jnl: plot over the vertical grid of a plot
xgridlines.jnl: plot over the vertical grid of a plot
ygridlines.jnl: plot over the horizontal grid of a plot

the gridlines, xgridlines, ygridlines, tgridlines use the ideas in Jaison's post and use the old and unsupported command ALINE (which works ok in x and y but not in time).

the gridxy.jnl etc scripts use contouring.

jagadish karmacharya wrote:
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?

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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