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Re: White band at edge of domain



Steve,

The LAS users mail server is back up.  Would you please rephrase the problem for those not aware of the email thread and post it there.  I just don't have the time to devote serious brain cells to this as a few other pressing issues have cropped up this week and I don't expect I'll get back to your problem.


-- Jon


Steve Cousins wrote:
On Wed, 28 Jan 2004, Joe McLean wrote:

  
Hi Steve,

Did you remove the old gif and html files from your las/server/output directory?
If the image still has the white band through LAS, and you have set up Ferret
correctly, thi smay be the problem.  You can tell which gif it is by using "view
source" in your popular browser and finding the href attribute pointing to the
image.  The html page in the output directory should have the same prefix.

Joe
    

Hi Joe,

Yes, I cleaned out the output directory when trying it with LAS.  I also
selected new areas and used different variables to make sure it wasn't a
caching problem (either with the server or the browser).  

Steve


  
-------------------------------------------------

Steve Cousins wrote:

    
On Tue, 27 Jan 2004, Jonathan Callahan wrote:

        
Steve,

The first thing that occurs to me is that the modulo flag might not be
set for the longitude axis in the netCDF file.  This would cause the
behavior you describe.
          
Hi Jon,

I've changed the data set to have:

dimensions:
        time = UNLIMITED ; // (12 currently)
        latitude = 116 ;
        longitude = 100 ;
        depth = 25 ;
        latitude_u = 116 ;
        longitude_u = 100 ;
variables:
        float time(time) ;
                time:long_name = "time" ;
                time:units = "months since 15-DEC-2003 00:00:00" ;
                time:time_origin = "15-DEC-2003 00:00:00" ;
                time:modulo = " " ;
        float latitude(latitude) ;
                latitude:units = "degrees" ;
                latitude:long_name = "Latitude" ;
        float longitude(longitude) ;
                longitude:units = "degrees" ;
                longitude:long_name = "Longitude" ;
                longitude:modulo = " " ;
        float latitude_u(latitude_u) ;
                latitude_u:units = "degrees" ;
        float longitude_u(longitude_u) ;
                longitude_u:units = "degrees" ;
                longitude_u:modulo = " " ;

etc.

Unfortunately it doesn't help as far as Ferret goes.  Ansley suggested a
quick test doing:

        define axis/modulo axisname

I tried a number of variations of this with no luck, however, I was
successful with:

        set axis/modulo longitude

So, that works with Ferret.  The data I'm working with is actually on a
restricted LAS server and LAS doesn't seem to be picking up the
information about the modulo longitude variable (I did addXml.pl and then
make) or something else is going on because LAS still shows the White
line.

With the modulo attribute set in the netCDF file should I have to do
anything else in Ferret (define axis, or set axis) in order to have ferret
overlap the longitudes correctly?  With modulo set should I be able to do:

use l.nc
fill/X=-180:180/k=5/t=1 DIAT

and not have the line under Africa?  Currently this works only if I also
do: set axis/modulo longitude.  This would be fine if I was just using
Ferret, but with LAS it might complicate things a little.  Do I need to
put something in the las.xml file for this?  Depending on the answers I
get above I'll move my questions to the LAS email list.

Thanks very much,

Steve

        
-- Jon


Steve Cousins wrote:

          
Hi,

I have a netCDF file that has longitudes from 23.4 degrees to 379.8
degrees stepping by 3.6 degrees.

longitude = 23.4, 27, 30.6, 34.2, 37.8, 41.4, 45, 48.6, 52.2, 55.8, 59.4,
63, 66.6, 70.2, 73.8, 77.4, 81, 84.6, 88.2, 91.8, 95.4, 99, 102.6, 106.2,
109.8, 113.4, 117, 120.6, 124.2, 127.8, 131.4, 135, 138.6, 142.2, 145.8,
149.4, 153, 156.6, 160.2, 163.8, 167.4, 171, 174.6,178.2, 181.8, 185.4,
189, 192.6, 196.2, 199.8, 203.4, 207, 210.6, 214.2, 217.8, 221.4, 225,
228.6, 232.2, 235.8, 239.4, 243, 246.6, 250.2, 253.8, 257.4, 261, 264.6,
268.2, 271.8, 275.4, 279, 282.6, 286.2, 289.8, 293.4, 297, 300.6, 304.2,
307.8, 311.4, 315, 318.6, 322.2, 325.8, 329.4, 333, 336.6, 340.2, 343.8,
347.4, 351, 354.6, 358.2, 361.8, 365.4, 369, 372.6, 376.2, 379.8 ;

If I do:

   fill/k=1/l=1 SSH

It looks fine.  If I do:

   fill/i=21:120/k=1/l=1 SSH

to shift the the plot then there is a vertical white line that goes
through Africa.  You can see this at:

   http://rocky.umeoce.maine.edu/images/problem.gif

I assume this has to do with some overlap problem but I
haven't seen it before with other similar data sets.  I've checked the
data and there is data in the last column so it shouldn't be interpreted
as land.  For instance:

 379.4641, 382.4534, 358.5003, 356.5043, 353.662, 359.2267, 365.5977,
   369.4947, 392.3723, 374.757, 372.0594, 389.124, 390.5706, 391.9053,
   393.023, 397.463, 375.3581, 371.0126, 372.924, 392.4577, 373.5735,
   364.2137, 364.4178, 372.6771, 392.912, 378.2903, 369.8222, 391.9157,
   370.6215, 371.5577, 371.0256, 377.0153, 374.279, 386.7569, 390.8015,
   371.6572, 365.4334, 366.7746, 364.0185, 362.7578, 379.4369, 377.3554,
   375.8331, 376.2615, 376.9933, 378.4856, 379.1119, 369.9149, 373.0526,
   376.518, 378.6648, 381.4642, 382.6173, 383.2715, 384.5013, 384.4879,
   384.6168, 386.2058, 386.3334, 384.5129, 383.7413, 384.0238, 384.1737,
   384.5389, 384.4421, 382.0946, 380.4161, 384.2753, 386.06, 384.2455,
   383.0246, 381.7079, 383.1534, 385.2602, 386.4101, 370.0849, -1e+34,
   368.7702, 362.1729, 358.6587, 360.2878, 362.5882, 363.6682, 367.4212,
   374.6625, 380.5357, 384.4504, 386.2372, 387.3375, 386.3895, 383.0319,
   381.321, 381.4418, 383.392, 382.2667, 382.2667, 380.2295, 376.7909,
   379.5762, 378.9742,

This is at 66 degrees South which has valid entries for almost all of the
horizontal grid points.  -1e+34 is the land value.

Has anyone seen this before?  Any ideas about how to bridge the gap?  This
is version 5.51 on a Redhat Linux 7.3 server.

Thanks,

Steve
_____________________________________________________________
Steve Cousins                 Email: cousins@umit.maine.edu
Research Associate            Phone: (207) 581-4302
Ocean Modeling Group
School of Marine Sciences     208 Libby Hall
University of Maine           Orono, Maine 04469




              
            
      

  

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