Glynn, Thanks for your help. Sorry that I was vague about what I was after. It looks like the first one is what I want, because I do want white to represent 0 difference.
Regards, Tom ----- Original Message ----- From: Glynn Clements <[EMAIL PROTECTED]> Date: Friday, October 19, 2007 4:32 pm Subject: Re: [GRASS-user] Need for a custom color map > > Thomas Adams wrote: > > > I'm wondering if someone has a color map that has white in the > middle > > range and blue at one extreme and red at the other. I'm creating > a > > precipitation difference map for data quality control purposes > and I'm > > trying to identify areas of over- and under-estimation by radar > > estimates relative to gauge-only estimates. Such a scale would be > > helpful to those looking for differences. > > The "differences" map (i.e. "r.colors ... color=differences") is: > > 0% blue > 0 white > 100% red > > This may be suitable, depending upon what you mean by "white in the > middle". The above has white at zero, which isn't necessarily the > middle. If you want white at the midpoint between the minimum and > maximum values, use: > > 0% blue > 50% white > 100% red > > If you want the table to be symmetrical, you'll need to specify > absolute values rather than percentages, e.g.: > > -10 blue > 0 white > 10 red > > -- > Glynn Clements <[EMAIL PROTECTED]> > _______________________________________________ grassuser mailing list grassuser@grass.itc.it http://grass.itc.it/mailman/listinfo/grassuser
