Re: xyz2grd

Dear Abhash,

As Paul suggested, you must use GMT surface and blockmedian commands in
order to fill in your area correctly with your data.

Also I noticed using matlab min max functions that your txt file includes
extended area than that given in the pdf file. This means that you entered
wrong borders as -R-78/-66/-20/-10.

I wrote a patch file to plot your data. You will find accordingly two ps
figures, Perugravity_notTrue (of border based on pdf file) and
Perugravity_True (of real borders based on txt file, i.e.
-R-81.27/-69.03/-18.25/-3.5).



Regards,

Basem

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Dr.-Eng. Basem Elsaka

Scientific Consultant

 

Center of Excellence for Lunar and Near Earth Objects Science,

King Abdulaziz City for Science and Technology (KACST),

P.O.Box  36484, Riyadh 11419, Saudi Arabia,

 

Tel: +966 503805697 | Fax: +966 114814572

Email: [email protected] | Website: http://www.kacst.edu.sa/en

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From: World-Wide GMT Usage and Help Mailing List
[mailto:[email protected]] On Behalf Of Paul Wessel
Sent: 04 March, 2014 2:18 AM
To: [email protected]
Subject: Re: [GMT-HELP] xyz2grd

 

I assume those "rivers" are the locations where you actually have data.

If you want to interpolate between these data you will need to consider a
2-D interpolation, a.k.a. gridding.

xyz2grd is not a gridder, it is a reformatter, mostly.  For gridding, see
examples in the gallery that uses surface, greenspline, triangulate, etc.

 

-p

 

On Mar 3, 2014, at 1:07 PM, Mr Abhash Kumar <[email protected]> wrote:





Hi,

I am using xyz2grd to convert the text file into grid file as follows:

 

xyz2grd Perugravity.txt -R-78/-66/-20/-9 -I1k -GPerugravity.grd -V

 

and then trying to get image of the grid file:

 

system "grdimage -Y2i Perugravity.grd $rflag $jflag $bflag -C$cptfn2  -V -K
> $psfn\n";

 

Instead of getting a smooth grid surface of bouguer anomaly for the Peru
region, I am getting image with discrete branching like course of river
distributed all over. I have attached both the text file and the image of
the grid. I would extremely grateful for any suggestion.

 

Thanks

Abhash kumar

University of North Carolina at Chapel Hill

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[email protected] <Bouguer.pdf><Perugravity.txt>

 

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