Re: Draw coastal line in different sea depth levels.

[Ansley Manke <ansley@xxxxxxxxxxxxx>]

Hi all
- XBOX and YBOX are some of the  Ferret Pseudo-variables which give
information about the coordinates of a grid.  See "Ch3 Sec1.3. Pseudo-variables "
in the Ferret Users Guide at
http://ferret.pmel.noaa.gov/Ferret/Documentation/Users_Guide/current/fer_html.htm

It looks like we could use more index entries to point to these by name.

Ansley Manke


Namba Takaya wrote:

> Dear Dr. Mick Spillane
>
> Thank you for your script.
>
> I made it.
>
> One more thing I would like to know is xbox and ybox variables in your
> script.
> Could you tell me what are these variables?
>
> Thank you again
>
> Takaya Namba
>
> >From: Mick Spillane <spillane@pmel.noaa.gov>
> >To: Namba Takaya <takayanamba@hotmail.com>
> >CC: <ferret_users@ferret.wrc.noaa.gov>
> >Subject: Re: Draw coastal line in different sea depth levels.
> >Date: Wed, 25 Apr 2001 13:42:52 -0700 (PDT)
> >
> >Here is a way to draw the boundary of a mask using straight line
> >segments for the top, bottom, left, and right edges of grid cells
> >lying along the "land-sea" border.
> >
> >Example: The Gulf of Alaska
> >
> >use etopo20
> >region/x=180:270/y=45:60
> >shade rose
> >
> >let mask=if(rose[d=1] gt 0)then 1 else 0
> >go bounder
> >
> >where bounder.jnl is the following script
> >
> >  ! bounder.jnl : drawing the "land-sea" edge in a mask
> >
> >def grid/like=mask gm
> >let xl=x[g=gm]-xbox[g=gm]/2 ; let xr=x[g=gm]+xbox[g=gm]/2
> >let yb=y[g=gm]-ybox[g=gm]/2 ; let yt=y[g=gm]+ybox[g=gm]/2
> >! the left edge
> >let ylb=if(mask[x=@ddb] ne 0)then yb else 999
> >let ylt=if(mask[x=@ddb] ne 0)then yt else 999
> >! the right edge
> >let yrb=if(mask[x=@ddf] ne 0)then yb else 999
> >let yrt=if(mask[x=@ddf] ne 0)then yt else 999
> >! the bottom edge
> >let xbl=if(mask[y=@ddb] ne 0)then xl else 999
> >let xbr=if(mask[y=@ddb] ne 0)then xr else 999
> >! the top edge
> >let xtl=if(mask[y=@ddf] ne 0)then xl else 999
> >let xtr=if(mask[y=@ddf] ne 0)then xr else 999
> >
> >! list all edges to the file bounds.d ...
> >list/nohead/form=(4f8.2,' 999 999')/file=bounds.d/clob xl,ylb,xl,ylt
> >list/nohead/form=(4f8.2,' 999 999')/file=bounds.d/app  xr,yrb,xr,yrt
> >list/nohead/form=(4f8.2,' 999 999')/file=bounds.d/app  xbl,yb,xbr,yb
> >list/nohead/form=(4f8.2,' 999 999')/file=bounds.d/app  xtl,yt,xtr,yt
> >! ... then use grep to exclude the interior cells ...
> >sp rm bounds2.d                ! this may require the user to type y
> >sp grep -v 999.00 bounds.d > bounds2.d
> >
> >file/form=free/var=xx,yy/col=6 bounds2.d
> >set var/bad=999 xx ; set var/bad=999 yy
> >can region
> >plot/o/nolab/vs/line=1 xx,yy
> >
> >------
> >Note that if a very large region were set, or the mask had a very fine
> >resolution, the number of points in bounds2.d might exceed the 20000
> >or so default limit and the read statement would need to be replaced
> >with a gridded read.
> >
> >Mick Spillane
> >
> >
> >|--****--****-*---*---***--***--|____spillane@pmel.noaa.gov____|
> >|-*__---*-----*--*-*--*--*-*--*-|_SCIENCE APPLICATIONS SUPPORT_|
> >|--***--*-----*-*---*-***--***--|____EPIC/Ferret/PlotPlus______|
> >|-----*-*-----*-*****-*----*----|__Room 2070 Bldg#3 NOAA/PMEL__|
> >|-****---****-*-*---*-*----*----|____Phone_:_(206)526-6780_____|
> >
> >
>
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--
Ansley Manke  Pacific Marine Environmental Laboratory  Seattle WA  (206)526-6246