Marine Data Literacy 2.0

Providing instruction for managing, converting, analyzing and displaying oceanographic station data, marine meteorological data, GIS-compatible marine and coastal data or model simulations, and mapped remote sensing imagery

 

 

 

 

Home > 9. Operational/Synoptic > 9.15 Recent GTSPP

9.15 Visualizing Real-Time Temperature/Salinity Profiles in IDV:  GTSPP

  • Exercise Title:  Visualizing Recent Temperature/Salinity Profiles in IDV:  GTSPP

  • Abstract:  In this exercise you'll learn how to take Global Temperature and Salinity Profile Program (GTSPP) data in the operational direction, by loading and displaying in Integrated Data Viewer (IDV).  [The alternate "direction" for use of these data is incorporation into archive style data collections with Ocean Data View (ODV)].  Quite frankly, this exercise is just a foot in the door with the introduction of GTSPP data to the IDV environment, which is more widely known and used for atmospheric data and simulations.  The data are loaded into IDV through a THREDDS catalog interface, and then very basically displayed as 2D and 3D images.  Issues about obviously needed scalability (e.g. multiple stations rather than only one) are briefly discussed.

  • Preliminary Reading (in OceanTeacher, unless otherwise indicated):

  • Required Software:

  • Other Resources: 

  • Authors:  Yuan Ho, Rich Signell, Charles Sun

  • Illustrations:  Murray Brown

  • Version:  March 2012

IMPORTANT NEW INFORMATION:  Recently the Saga GIS software has been shown to deal quite adequately with most NetCDF (NC) data grids (and possibly also GRIB files).  This should be viewed as a useful addition to the rapid, direct NC analysis and display capabilities of IDV (see below).  If you are also interested in this route for your data, then please check Viewing and Managing Well-Formed NetCDF Grids in Saga.
1.  This exercise is provided just to show how the connection can be made between the GTSPP data and IDV, in the first instance.  Because the author is not an expert on the many imaginative display graphics and methods available in IDV, the attempt here is very elementary and offered only to stimulate thinking and experiments by students.  The final product here, a color-coded profile in 3-D space, is not terribly impressive, also it immediately begs questions about the future use of multiple profiles (does each one take all the steps you see below?) and how to place these figures on maps (currently they appear in lat/lon space, but without any base map).
2.  If you have IDV 3.0u2 or earlier, then you probably do not have the gtspp.jar plugin (above).  Run IDV and use TOOLS > PLUGIN MGR to install it.  Then restart IDV.
3.  Find (or open) the dashboard control window to DATA CHOOSERS, and in the menu on the left side select CATALOGS.
4.  Insert the above THREDDS catalog URL in the space by CATALOGS, and for DATA SOURCE TYPE, select GTSPP files.

 

5.  When the list of files appears (after a few minutes!) then scroll to the bottom and select a file.

Then click ADD SOURCE.

6.  After a short wait, the FIELD SELECTOR will open.  Navigate into the 3D GRID menu to find the available variables.
7.  We' re going to use two methods to display the data, a VERTICAL PROFILE to see a temperature-depth plot, and then a VOLUME RENDERING to see the data displayed in 3D.

NOTE:  We could, of course, have chosen salinity for the variable of interest.  That is up to you, and you can substitute it in the steps that follow.

8.  Select TEMPERATURE as the field, and then select VERTICAL PROFILE for the display.
9.  In the bottom right corner, select LEVEL > ALL LEVELS

Then click CREATE DISPLAY.

10.  This relatively uninteresting "map" appears in the main IDV window, but there is an interesting graph on the right side, under VERTICAL PROFILE.
11.  Click VERTICAL PROFILE (in the legend on the right), and this graph opens.
12.  If the data ranges are too big or too small, right-click on the graph, and select AUTO RANGE > ALL AXES.
13.  The axes are adjusted, and this better figure appears.
14.  You can see above that the depth range is from zero to 500 m.  We can set this in IDV by finding and clicking the VERTICAL SCALE control on the left margin of the main map (looks like a comb).
15.  Set the desired range values, taking care to use a negative sign for marine data, and the proper sense of MIN and MAX.

Then click OK.

16.  Now you can uncheck the VERTICAL PROFILE item in the legend, to turn it off.
17.  In the dashboard, go back to the DISPLAYS menu, and select VOLUME RENDERING > VOLUME RENDERING.  Set ALL LEVELS, then click CREATE DISPLAY at the bottom.
18.  The dashboard appears, already set up for the VOLUME RENDERING display.  Notice that the temperature scale is too large.
19.  Click on TEMPERATURE and select CHANGE RANGE.
20.  Now at this point, if you have one, you can insert a range you have selected for this area or for this time.  That is something you can decide later after you have studied your own data.

For now, we'll take USE PREDEFINED > FROM ALL DATA.

21.  Click the TEMPERATURE control again, and examine the 5 sets of color palettes that appear at the bottom of the drop-down menu.

Of these, just select the first RADAR palette, which comes closest to the range of color in nature.  You can make other choices on your own later.

22.  Now you have these values set.  They are on the dashboard, so don't close it.
23.  Just switch to the main IDV map, and look in the legend on the right to make sure you have these objects.

The VERTICAL PROFILE (not checked).

The VOLUME RENDERING with the range and palette we have just chosen.

You can click on either item to open the dashboard for it, and make changes if you need them.

24.  But this is what you see in the main map.  Just a square box and a tiny colored dot in the middle.
25.  Place your cursor in the bottom right corner of the square, and use right-click to grab it and rotate it in 3D space.

Here you can see the whole temperature profile, color coded with the selected palette.

26.  This is merely an introduction to the use of IDV with GTSPP data, resulting in one simple profile.  Obviously, if you explore the "layouts" offered by IDV (pre-designed graphical presentations of the data), you'll see many interesting ideas for improved displays.  We invite you to explore all this on your own.  There are ideas being floated now about using aggregate files (containing more than one NetCDF profile), temporal and spatial subsetting (to reduce the amount of data), and other display modes.
27.  Use FILE > SAVE AS and navigate to the folder PRODUCTS > IDV to save the current data and display parameters with a appropriate filename, such as temp_201203_13693413te_gtspp_nrt_volrender.xidv