Concatenating multiple grb files

Useful hints
Post Reply
User avatar
Rick
Posts: 404
Joined: Fri Jan 16, 2009 8:20 pm

Concatenating multiple grb files

Post by Rick »

You can get archived forecast data from:

http://nomads.ncdc.noaa.gov

Generally you'll get multiple files for each model run or forecast hour for a particular model run. These files can be concatenated and make displaying data much easier. For example, I had the following files:

nam_218_20101026_0000_000.grb nam_218_20101026_0000_024.grb nam_218_20101026_0000_048.grb nam_218_20101026_0000_072.grb
nam_218_20101026_0000_003.grb nam_218_20101026_0000_027.grb nam_218_20101026_0000_051.grb nam_218_20101026_0000_075.grb
nam_218_20101026_0000_006.grb nam_218_20101026_0000_030.grb nam_218_20101026_0000_054.grb nam_218_20101026_0000_078.grb
nam_218_20101026_0000_009.grb nam_218_20101026_0000_033.grb nam_218_20101026_0000_057.grb nam_218_20101026_0000_081.grb
nam_218_20101026_0000_012.grb nam_218_20101026_0000_036.grb nam_218_20101026_0000_060.grb nam_218_20101026_0000_084.grb
nam_218_20101026_0000_015.grb nam_218_20101026_0000_039.grb nam_218_20101026_0000_063.grb
nam_218_20101026_0000_018.grb nam_218_20101026_0000_042.grb nam_218_20101026_0000_066.grb
nam_218_20101026_0000_021.grb nam_218_20101026_0000_045.grb nam_218_20101026_0000_069.grb

Running the following command created on grb file that had all the forecast hours contained with in one file:
cat nam*.grb > NAM-26-Oct-2010-00Z.grb
User avatar
jayh
Posts: 414
Joined: Thu Jan 15, 2009 10:34 pm

Re: Concatenating multiple grb files

Post by jayh »

There is a formula available in the Field Selector's "Formulas" list that is able to do this type of display without the need to cat together the grib files.

In the Data Sources tab, select the grib files from which you want to use the data. Click Add Source, and from the Formulas list in the Field Selector, you can choose Miscellaneous -> Make a time sequence from single time grids/images. A selector window will appear and you can add multiple fields from multiple times by clicking "Add selected" and each field you want to put in your sequence will be added to the list.

Hope this information helps.

Thanks, Jay
McIDAS User Services
Post Reply