Re: xyz2grd

Hi Basem,

I am grateful for your concerned reply. I am not able to open the patch file you sent to me because it is blocked. It would be a great favor if you can copy the flags and their values you used for blockmean and surface to create the grid image. I am using the same color paltte and blockmean as well as surface as follows:


system "blockmean Perugravity.txt -R-78/-66/-20/-10 -I0.1 > smoothedvals.txt\n";
system "surface smoothedvals.txt -S20k -GPerugravity.grd -I2k -A0.966 $rflag -Ll-450 -Lu50 -T1 -V\n";
system "grdimage -Y2i Perugravity.grd $rflag $jflag $bflag -Cpallete.cpt  -V -K > $psfn\n";


But my grid image is significantly different than your image.


Regards

Abhash kumar

University of North Carolina at Chapel Hill

________________________________
From: World-Wide GMT Usage and Help Mailing List <[email protected]> on behalf of basem elsaka <[email protected]>
Sent: Tuesday, March 4, 2014 2:21 AM
To: [email protected]
Subject: Re: [GMT-HELP] 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
------------------------------------------------------------------------------------
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
------------------------------------------------------------------------------------



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]<mailto:[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
To unsubscribe, send the message "signoff gmt-help" to [email protected]<mailto:[email protected]> <Bouguer.pdf><Perugravity.txt>

To unsubscribe, send the message "signoff gmt-help" to [email protected]<mailto:[email protected]>
To unsubscribe, send the message "signoff gmt-help" to [email protected]

To unsubscribe, send the message "signoff gmt-help" to [email protected]