Re: grdgradient and -R specifications

Cyril Langlois <[email protected]>
Newsgroups gmane.comp.gis.gmt.user
Message-ID <[email protected]>
Hi,

grdinfo on the WGM2012_Bouguer_ponc_2min.grd grid says :

WGM2012_Bouguer_ponc_2min.grd: Title: /data/xxgrgs/vales/CARTE_GRAVI/TRACES/BOUGUER_DTU10L/Bouguer_DTU10L_ponc_2mn.gr
WGM2012_Bouguer_ponc_2min.grd: Command: xyz2grd -V -R-180.0/+180.0/-90.0/+90.0 -I2m /data/xxgrgs/vales/CARTE_GRAVI/BOUGUER_avec_DTU10L/Anomalie_Bouguer_spherique_globale_ponc_2mn_avec_DTU10L.xyz -G/data/xxgrgs/vales/CARTE_GRAVI/TRACES/BOUGUER_DTU10L/Bouguer_DTU10L_ponc_2mn.grd
WGM2012_Bouguer_ponc_2min.grd: Remark: 
WGM2012_Bouguer_ponc_2min.grd: Gridline node registration used [Cartesian grid]
WGM2012_Bouguer_ponc_2min.grd: Grid file format: nf = GMT netCDF format (32-bit float), COARDS, CF-1.5
WGM2012_Bouguer_ponc_2min.grd: x_min: -180 x_max: 180 x_inc: 0.0333333333333 name: x nx: 10801
WGM2012_Bouguer_ponc_2min.grd: y_min: -90 y_max: 90 y_inc: 0.0333333333333 name: y ny: 5401
WGM2012_Bouguer_ponc_2min.grd: z_min: -528.964355469 z_max: 1005.01184082 name: z
WGM2012_Bouguer_ponc_2min.grd: scale_factor: 1 add_offset: 0
WGM2012_Bouguer_ponc_2min.grd: format: classic

So it seems to be a normal geographic grid ?
 
Cyril 

Le 3 déc. 2013 à 22:33, Paul Wessel <[email protected]> a écrit :

> Perhaps the $grid file was not created as a geographic grid? Does grdinfo say degrees_east and degrees_east as units? If not you might need to add -fg to the command.
> 
> -p
> 
> On Dec 3, 2013, at 11:18 AM, Cyril Langlois <[email protected]> wrote:
> 
>> Hello,
>> 
>> I want to use the global Bouguer anomalies model WGM2012 available at BGI site (http://bgi.obs-mip.fr/fr/data-products/Grids-and-models/wgm2012) with GMT5.1.0 for the Hawaii-Emperor islands. Then, I want to extract the region -R150/220/0/60 from the grid file. So I write : 
>> 
>> gmt grdgradient $grid -R150/220/0/60 -A270 -GBouguer_intens.grd -Ne0.6
>> 
>> where $grid calls WGM2012_Bouguer_ponc_2min.grd
>> 
>> But the output image shows data only between 150°W and 180°, as if grdgradient could not pass from -180/180 to 0/360 longitudes data. Without -R specification, the map is correct (but the running time is delayed) ! I don’t understand...
>> 
>> My script is attached below. 
>> 
>> Thanks for help,
>> Cyril
>> 
>> To unsubscribe, send the message "signoff gmt-help" to [email protected] <GMT5_Hawaii-Empereur_Bouguer_WGM2012.sh>
>> 
>> Dr. Cyril LANGLOIS
>> Professeur agrégé - enseignant de Sciences de la Terre 
>> [email protected]
>> Tél. portable : 06 89 05 68 22
>> Tél. bureau : 04 72 72 85 28
>> § --------------------------- §
>> Préparation à l'Agrégation SV-STU
>> Ecole Normale Supérieure de Lyon -  Site Monod
>> 46, allée d'Italie
>> 69364 Lyon cedex 07
>> § --------------------------- §
>> 
>> To unsubscribe, send the message "signoff gmt-help" to [email protected]
> 
> To unsubscribe, send the message "signoff gmt-help" to [email protected]

Dr. Cyril LANGLOIS
Professeur agrégé - enseignant de Sciences de la Terre 
[email protected]
Tél. portable : 06 89 05 68 22
Tél. bureau : 04 72 72 85 28
§ --------------------------- §
Préparation à l'Agrégation SV-STU
Ecole Normale Supérieure de Lyon -  Site Monod
46, allée d'Italie
69364 Lyon cedex 07
§ --------------------------- §


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