Re: FW: [GMT-HELP] Fwd: How to make a non-symmetric color pallet around zero

Hallo Basem,

how about if you just make two calls and then paste it together, then you use the final cpt. Something like this (untested):

makecpt -Z -Chaxby -T-75/0/25 -N > cpt1
makecpt -Z -Crainbow -T0/150/50 -N > cpt2
cat cpt1 cpt2 > cpt

would that help?

Prost,

Gery

__________________________________________________________________________________________
Piensa en el medio ambiente - mantenlo en la pantalla. NO lo imprimas si NO es necesario.
Think green - keep it on the screen. Do NOT print if it is NOT necessary.
Denken Sie an die Umwelt - bewahren Sie es auf dem Bildschirm. Drucken Sie es NICHT, wenn es NICHT notwendig ist.


> Date: Wed, 15 Jan 2014 09:21:29 +0300
> From: [email protected]
> Subject: [GMT-HELP] FW: [GMT-HELP] Fwd: How to make a non-symmetric color pallet around zero
> To: [email protected]
> 
> Sorry I forgot the attachment
> 
> -----Original Message-----
> From: basem elsaka [mailto:[email protected]] 
> Sent: 15 January, 2014 9:21 AM
> To: Help Mailing List ([email protected])
> Subject: RE: [GMT-HELP] Fwd: How to make a non-symmetric color pallet around
> zero
> 
> Hallo Walter, here is the same output
> Nothing changed by multiplying the +ve values by 2.
> The main problem as I think and addressed before is in psscale -B option. Is
> there any solution to divide from -75 to 0 every 25 and divide 0 to 150
> every 50 at the same time??? Then one can easily get symmetric scale around
> zero, despite of different numbers.
> I think it is a hard jop using GMT. Or not?
> Basem
> 
> -----Original Message-----
> From: Walter (HF) Smith [mailto:[email protected]]
> Sent: 14 January, 2014 3:04 PM
> To: [email protected]
> Cc: [email protected]
> Subject: Re: [GMT-HELP] Fwd: How to make a non-symmetric color pallet around
> zero
> 
> Why can't you use makecpt to generate from -75 to +75 with steps of 25, and
> then use awk to multiply the positive values by two?
> 
> 
> On Jan 14, 2014, at 6:17 AM, basem elsaka wrote:
> 
> > Hallo Shahar,
> > I have the same problem like you. I'm trying to make symmetric 
> > colorbar from non-symmetric color scale As you can see in the attached 
> > map, I'm trying to plot from -75 to zero every 25 spacing and from 0 
> > to 150 every 50. My target is from -75 to 150 only 6 spacing (3 
> > negative and 3 positive).
> > There are mainly three problems:
> > 1- as mentioned (symmetric spacing issue)
> > 2- how to play with -B option in psscale to be -B25 and -B50 at the 
> > same time ?? is there an option in psscale that is similar to -T in
> makecpt?
> > 3- how to make continuous colorbar in makecpt after appending the file 
> > with -N option? Because as you see nobody can distinguish between 
> > negative and positive values.
> > Of course writing the following will lead to another color series (see 
> > 2nd
> > attachment)
> > 
> > makecpt -Z -Chaxby -T-75.0/0.0/25.0  -N > paletteTwice.cpt makecpt -Z 
> > -Crainbow -T0.0/150.0/50.0 >> paletteTwice.cpt
> > 
> > So did you or anyone succeed to solve this problem. Anyone has 
> > suggestions, pleeeeez
> > 
> > Basem
> > Institute of Geodesy and Geoinformation, Bonn, Germany
> > Currently: KACST, Saudi Arabia
> > 
> > 
> > -----Original Message-----
> > From: World-Wide GMT Usage and Help Mailing List 
> > [mailto:[email protected]] On Behalf Of Paul Wessel
> > Sent: 08 January, 2014 2:14 AM
> > To: [email protected]
> > Subject: [Bulk] Re: [GMT-HELP] Fwd: How to make a non-symmetric color 
> > pallet around zero
> > 
> > In GMT5 see makecpt's new option -G for selecting just part of an 
> > incoming cpt range.  You can then run makecpt twice; first for the 
> > negative values and you stretch those via your -Tmin/0/inc and then 
> > append the positive side stretched with -T0/max/inc, using -N during the
> first call.
> > in GMT4 you'll need to do some awking.
> > 
> > -p
> > 
> > On Jan 7, 2014, at 12:53 PM, Shahar Barak <[email protected]> wrote:
> > 
> >> Hi,
> >> 
> >> I'm trying to plot a figure that shows velocity perturbations by 
> >> color (results of seismic tomography). I want values at zero and 
> >> around zero to be white, but I don't want the color pallet to be 
> >> symmetric. The minimum and maximum values are different.
> >> In order to force white to be around zero I use grd2cpt with the -T 
> >> option, however this forces the color pallet to be symmetric.
> >> Any ideas on how to accomplish this? I need it to be automated, i.e, 
> >> not by manually editing the CPT file.
> >> 
> >> Thanks,
> >> 
> >> Shahar
> >> 
> >> To unsubscribe, send the message "signoff gmt-help" to 
> >> [email protected]
> > 
> > To unsubscribe, send the message "signoff gmt-help" to 
> > [email protected]
> > 
> > To unsubscribe, send the message "signoff gmt-help" to 
> > [email protected] <symmetric_scale.jpg><symmetric_scale_2.jpg>
> 
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