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 > 5. Gridded Data > 5.18 ToolsUI Convert

5.18 Convert GRIB Format to NetCDF with ToolsUI from UNIDATA

1.  Save the above GRIB2 file to a suitable work location on your computer.
2.  If your don't already have the Java Runtime Environment on your computer, then go to the JRE site, above, and install it.

HINT:  You know you don't have it, if you can't run JAR files by clicking on them.

3.  Download ToolsUI.jar (latest version) to any convenient location where you can find it later.

NOTE:  Today the MDL author finds the latest version is 4.5.  Please see if you are also using the software Environmental Data Connector (EDC), which includes version 4.3.  You might want to make a manual upgrade to EDC.

4.  Run ToolsUI by clicking on the filename.

This is a very powerful program with many many aspects we won't touch on in this very simple exercise.  In fact the program Environmental Data Connector (EDC) can roughly be considered as a user-friendly interface to parts of ToolsUI.

5.  Find and click the OPEN LOCAL DATASET control along the top left.
6.  Use the FILE CHOOSER to find and select the GRIB2 file in the work location.

7.  After ToolsUI examines the file, you can see this summary of its contents under the VIEWER tab.  You take a little time to see what's really in the file.

8.  Click on the WRITER tab along the top margin, to see the options for exporting this file, i.e. converting to a different format.  Open the different dropping menus to see what's available.

9.  Make these choices:

  • OUTPUT FILENAME:  Create a new name that includes part of the old name, but make sure it ends in _grib2 to remind you of the original format.  Use NC3 for the extension to match the format choice in the next item.  And for your information, ToolsUI will write the file to the same folder where you stored ToolsUI.jar.

  • NetCDF FORMAT:  The author selected NetCDF3, but you can do what you want.  For simplicity, match up this format with the extension you created above.

  • CHUNKING:  For a GRIB original file, use GRIB.  The author learned this by testing the product file in ncBrowse and Saga and advises you to do the same.  The NetCDF option, for this test file, results in a file that does not have latitude/longitude coordinates.

Then click WRITE FILE to perform the conversion

10.  This message indicates you were successful.  Click OK.
11.  The product file appears now in the same folder with the ToolsUI.jar executable
12.  Here's the file displayed as a map in ncBrowse, showing geographic coordinates.  Use of ncBrowse is the quickest, most reliable method to check NetCDF files.

This view, with the Atlantic on the left is not the usual method.  See the last Panel in the exercise to see how to change it.

13.  You can also check the files in Saga.
14.  Use TOOLS > IMPORT/EXPORT > GDAL/OGR > IMPORT RASTER.

Then make these choices, and click OK.

15.  Select only the temperature data.  The REFTIME looks like a date/time variable.
16.  This new data object appears.  You can see that it has a lower-left corner (X and Y locations) very near the south pole.  The cell dimension, 0.083333, is the same as 1/12

17.  And here are the data displayed as a map in Saga.  The color palette information is included in the options for your use, because the original view is simply a gray-scale image.

18.  You can convert the view of these data to our usual Atlantic-centered format with the exercise 5.16 Converting Between 0-to-360 and -180-to-180 Grids in Saga