Tutorial: Use GrADS to draw shapefiles

Here we go with yet another tutorial on using shapefiles in GrADS.  This one is slightly more advanced than the other tutorials I have on this site: here and here.  The reason it is a little more advanced is that, in this tutorial we will now use GrADS to create shapefiles...

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Script: theta.gs; Defines potential and equlivalent potential temperature given temperature and moisture inputs

This script, is really more of a function, the best way to use this would be to copy the contents of this script into the bottom of the script you wish to use it in.  This function reads in temperature and moisture information and returns a good approximation of both potential and equivalent potential temperature. This function asks for up to...

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Some tips on running GrADS from the Windows Command Line and .bat scripts

If you are using GrADS through a linux operating system, chances are you are familiar with running GrADS from the command line, so this post is mostly aimed at the Windows users.  This post will go through the basic instructions for running GrADS from your command line along with arguments and options.  So lets first begin with a question. Why...

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Script: checkered.gs; Draws a black/white checkered border around the outside of your map.

This script helps you create more professional looking area maps by plotting a clean border around your map.  An example is shown here: World map plotted with checkered border. Required Arguments: There are no required arguments for checkered.gs Options: -help(-h)  ...

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Script: us_map.gs; Draws and saves map of the United States with Alaska and Hawaii in the lower left corner

This script gives you the ability to generate the classic US map that has helped convince countless of Americans that Alaska is really an island near Mexico, and not a giant landmass far to the north. Required Arguments: -var: chosen plot variable Options:   -help(-h): ...

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Tutorial: Shapefile; A look at the DBF file.

This is the 2nd tutorial on using shapefiles in GrADS.  If this is your first time using shapefiles in GrADS, it is recommended you check out this tutorial.  This tutorial will dig a little deeper and look at the 'q dbf' command to look at the different shapefile properties. ...

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Tutorial: Draw arbitrary cross-section with terrain in pressure coordinates using GrADS

As mentioned in the introductory post, one of the major deficiencies with GrADS, is that drawing arbitrary vertical cross-sections is not an easy task.  There are however work-arounds to do this, but they can be quite complex, especially when including terrain.  This...

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Script: Dynamic: Calculates temperature and vorticity advection, Q-vectors, deformation, geostrophic and ageostrophic winds, and Fronogenesis in GrADS

Usually, more advanced dynamic variables like frontogenesis and deformation are not included in the list of variables in your model output files.  Instead, it is up to the user to calculate them from the available wind and temperature fields.  Calculating these variables...

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Tips on using the finite differencing functions in GrADS (e.g., hdivg, and hcurl): Getting rid the undefined strip along the map boundary

The finite differencing functions in GrADS are pretty handy, especially when it comes to plotting variables such as divergence. The finite differencing function used in GrADS is called cdiff(), and what cdiff() does, is simply take the finite difference of a certain variable....

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Tutorial: Use the tcorr function to create a map of regression/correlation coefficients in GrADS

Making a correlation map in GrADS is actually quite simple.  A regression/correlation map, is basically a map of regression and correlation coefficients plotted against a time-series of some variable.  The classic example is the monthly average time-series of El-Nino...

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A look at the different map projections in GrADS

There are a number of different possible map projections you can use in GrADS, and you may be familiar with some, or all of them, or perhaps you are only familiar with the standard default lat/lon projection used.  This entry will be less of a tutorial and more of just...

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