J-LAS and Merged Data Product Tutorial

Cyndy Chandler, US JGOFS DMO

from October 2001 presentation

at Woods Hole Oceanographic Institution

 

J-LAS is the US JGOFS customized version of the Live Access Server (LAS) developed at NOAA/PMEL by Steve Hankin, Jon Callahan and Joe Sirott.  As of February 2002, this software is still a Beta release.

 

To begin:  start up an Internet browser (Netscape or Internet Explorer) and

open a file from Cyndy Chandler’s web page:

URL is  http://usjgofs.whoi.edu/datasys/JLAS_class/J-LASclass.html

 

Select one of the links from the J-LAS class page.

 

 

Some J-LAS Hints

 

There are three distinct areas in the main J-LAS screen.  The title bar across the top includes a server title in the center (US JGOFS Process Studies) and four link buttons to the right.

      

 

 

Help:    generic LAS help                      Options:  modify Ferret settings

Home:  will go to US JGOFS                Ferret:   goes to Ferret Home

 

Data sets are listed in the left frame. Click on the name of a data set to expand it and view a list of available variables.  Click on a variable name to select that variable within the expanded data set.  The variable name should appear in the frame to the right.  [Single variable only in this release.]

 

Select  to display documentation window.

 

 

 

 

 

ie. C_toN = Carbon to Nitrogen ratio; US JGOFS Arabian Sea Process Study Niskin samples

 

You can modify the data selection by adjusting spatial and temporal bounds:
Latitude, Longitude, Depth and Time ranges (XYZT respectively). 

 

You may change the viewing plane.  Select from: XY: Longitude v. Latitude

 XZ: Longitude v. Depth (view from East)

                                                                 YZ: Latitude v. Depth (view from South)

 

You may also wish to select a different product from the drop down list at the bottom of the screen.  Current choices include a variety of GIF images and download formats:

XY pie plot (GIF) to get an indication of sample locations on lat/lon map

XZ pie plot (GIF) for longitudinal depth section

YZ pie plot (GIF) for latitudinal depth section

XZ [YZ] Gaussian filled plot (GIF); algorithm used is a Gaussian weighted mean of input points where weights vary with Gaussian decay and independent cutoff value.

 

It is also possible to download the data in plain text format or as a NetCDF file.

 

When you have made desired adjustments to various ranges, choose Get Data to view your data (usually as a GIF image in a new window).

 

 


Enjoy ! The next few pages are printed from the generic LAS Help screen. Try some things out, have fun, ask questions when you get stuck. I’am very interested in knowing what you like about the interface and any suggestions you might care to share. Please keep in mind you are using a Beta release version.

 

 

cchandler@whoi.edu