Re: [ferret_users] Scales

[Ansley Manke <ansley.b.manke@xxxxxxxx>]

Hi-
By scale, are you talking about the set of values that translate into the color-scale?  You can use the /LEVELS qualifier to define the levels that you want to use.  Open-ended levels are useful so that extreme values don't appear as if they're missing data as they would if they went outside the range of closed-ended levels.  Also note the use of "KEYMARK" which labels the ends of your color bar with the actual range of the data.

If you've let Ferret create levels automatically, you can see what levels were used on a plot by looking at the symbols LEV* after the plot is drawn

yes? use coads_climatology
yes? shade/lev=v/L=1 slp

yes? sh sym lev*
LEV_TEXT = "V"
LEV_MIN = "973.2"
LEV_MAX = "1046.5"
LEV_NUM = "31"
LEV_DEL = "irregular"
LEV_OPNLEVS = "(-inf)(990,998,2)(999,1019,1)(1018,1028,2)(inf)"

(Try it without the /LEV=v too.)  Then you could use this information to set the color levels on other plots.  Maybe adjusting the levels a bit to be appropriate for the whole range of the data.

yes? define symbol my_levels = (-inf)(990,1000,2)(1000,1020,1)(1020,1030,2)(inf)
yes? shade/L=3/lev=($my_levels) slp

Or, if you have created a plot whose color scale you like, then for subsequent plots you can use /LEVELS alone and Ferret will re-use the same colors.

yes? shade/L=1 slp
yes? keymark 1    ! label the ends of the axis with the min and max of data in each plot
yes? shade/L=3/levels slp

There's more to all this, but see if this gets you started.

Ansley

On 8/25/2011 1:36 PM, Broadbent, Richard J. wrote:

Hello,

      I am modelling the change in Net primary productivity over time in an area of the USA for my masters thesis. My question is: I am displaying "shade" maps of the changes over each month but the scale is different on each map and I was wondering how it's possible to create a scale that is the same for all maps?

Many Thanks,

Richard Broadbent