Re: [las_users] Plot colour bar in ferret (fill level of Ferret Column Bar)

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

Hi-
For animations, the Ferret scripts first go through all of the data that will be animated, and compute a set of color levels that will work for all of them, using the same algorithm as for color levels on single plots.  In the two plots that you show I think that the computations for the animation colorbar happens to do better and give us a colorbar that doesn't go below zero.

Ferret itself could use more control over the open-ended color levels, so that if a variable such as rainfall can't have negative values, we could tell it to compute a set of color levels that are positive only.  Quoting from the Ferret documentation, here is what is done for the open-ended variance-based color levels:

Ferret finds the mean and standard deviation of the data to be color-filled or contoured. Within the range mean-minus 1 std to mean-plus 1 std, fine levels are chosen, and between 1 std and 2 std on each end, coarser levels are used. An open-ended level is used to represent values outside 2 std. The number of levels n is used as an approximate number of levels; the actual number is adjusted to select round numbers for the color levels. If the minimum or maximum of the data is inside the range (mean-2STD, mean+2STD), then the color bar will end with the last level that contains the min or max. Thus the levels may not be open-ended, or may be open-ended only on one end.

We could use a way to specify a hard lower or upper limit for the levels used, so that if the values shouldn't be negative or shouldn't be larger than some known value, we would have a way to tell Ferret that.

For the moment I think the best solution is for you to specify levels in the xml for your data.

On 4/5/2011 3:43 AM, sandip wrote:

Dear All,

In my previous post, I got the answer all of the questions. But still I am
looking to set the condition in Ferret rather than XML file.


Ques:- Range of column bar of the ferret map is starting from random minus
value instead of zero (It must start from zero) and some case like anomaly
    it should start from minus value. (for anomaly its showing right
values). How to set the colour bar range in ferret file?

*Mr. Ansley Manke* reply my previous mail and gave me valuable tips.
For setting of the ferret column bar in XML file (Its working fine in xml
file )

<variables>
      <RAIN-id-60f7e24b64 name="rainfall" units="mm" url="">
        <link
match="/lasdata/grids/grid-LONGITUDE-LATITUDE-TIME-id-60f7e24b64" />
           <properties>
              <ferret>
                 <fill_levels>(0,75,5)(75,155,10)(inf)</fill_levels>
              </ferret>
           </properties>
     </RAIN-id-60f7e24b64>


I want to set the ferret plot column bar values from zero to infinity (+ ve)
and for like anomaly i wanted to keep as it is.
(e.g. cumulative and Mean Rainfall is always positive but Anomaly may be
negative) *can we set the conditions in ferret file.*

Also one thing is that if we plot the animation, then its showing correct
values on column bar for all datasets.

Regular ferret image from LAS
[image: image1.png]
And Plot Animation image showing correct values

[image: plot_image.png]

Now my question is  which ferret called on Regular Plot  and Animation
Plot.  And is it possible to make the change in ferret file.

Waiting for reply.......