Re: [las_users] blank map when all data values negative

["John Maurer, IV" <jmaurer@xxxxxxxxxx>]

Thanks for the suggested workaround, Ansley, while that Ferret bug gets fixed. However, I cannot get the change to take effect. I'm still seeing the same problem despite having updated my config file the way you suggest (with fill_levels). I've tried clearing the LAS cache, clearing my browser's cache, and rebooting Tomcat. But I still get blank maps. Something else I need to run for this to take effect?
Cheers,
John

----- Original Message -----
From: Ansley Manke <Ansley.B.Manke@xxxxxxxx>
Date: Monday, January 3, 2011 9:25 am
Subject: Re: [las_users] blank map when all data values negative
To: "John Maurer, IV" <jmaurer@xxxxxxxxxx>
Cc: oar.pmel.las_users@xxxxxxxx

> Hi John,
> This looks like a bug in Ferret's computation of the color 
> levels, for those timesteps in your data with small negative 
> values.  We'll look into that. Meantime a workaround for 
> you would be to put a color_levels specification in the dataset 
> configuration xml file for this variable.
> 
> Specifying fill_levels of say, 30 would ask for approximately 30 
> equal-sized color levels.  Or, to have the levels centered 
> around zero, use 30c.
> 
> 
> <SSH-id-60f7e24b64 name="tidal elevation" units="meters" 
> url=""><link match="/lasdata/grids/grid-LONGITUDE-
> LATITUDE-TIME-id-60f7e24b64" />
> <properties>
> <ferret>
> <fill_levels>30</fill_levels>
> </ferret>
> </properties>
> </SSH-id-60f7e24b64>
> 
> On 12/30/2010 6:21 PM, John Maurer, IV wrote:
> > Hi LAS Folks,
> > Very happy with the new features in LAS 7.2.2 so far. Thanks! 
> One strange glitch I'm finding, though, that I was hoping 
> somebody could help me with. The following dataset produces 
> blank maps on some datetimes and successful color maps on 
> others. In looking at the colorbar that gets produced, I've 
> noticed that it only generates blank maps when the data values 
> all range in the negatives (e.g. -0.2272 to -0.1255 m). When the 
> upper range is positive, however, it successfully produces a map 
> (e.g. -0.006573 to 0.05996 m). You can try for yourself. The 
> following link defaults to Jan 01 2008 00:00 and produces a 
> blank map of tidal elevation for Hawaii:
> >
> >
> > 
> http://oos.soest.hawaii.edu/las/getUI.do?dsid=tide_elev_mhi&varid=ssh-tide_elev_mhi&auto=true <http://oos.soest.hawaii.edu/las/getUI.do?dsid=tide_elev_mhi&varid=ssh-tide_elev_mhi&auto=true>
> >
> >
> > If you increment the hour setting, you'll find that color maps 
> only get produced at 06:00-21:00, when there is a positive 
> maximum in the colorbar range. Successive days show a similar 
> pattern. At first I suspected something wrong with the dataset, 
> but it's getting successfully displayed in Godiva2, ERDDAP, and 
> DChart, and it was being correctly displayed in LAS V7.1.1. 
> Possibly a bug in how LAS V7.2.2 is selecting its colorbar?, or 
> some additional configuration that I'm missing? Ideas on what's wrong?
> > Thanks!,
> > John Maurer
> > Hawaii Ocean Observing System (HiOOS)
> > University of Hawaii