# Chad Greene

### NASA Jet Propulsion Laboratory

I am interested in the floating ice shelves that fringe East Antarctica. My current work is toward building a better understanding of how climatology influences glaciology via oceanography. I also have some experience with the acoustics of gas hydrates and oceanic methane bubbles.

Homepage: www.chadagreene.com

Professional Interests: Antarctic ice shelf dynamics, sea level rise, underwater acoustics, methane hydrates

Note: I will not do your homework for you and I will not respond to emails directing me to a question posed on the Answers forum.

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**Content Feed**

Can anyone help me with the a tentative guide on how to average across the two dimensions of a 3d array, and loop it across 86 timesteps?

If you have a temperature data cube T whose dimensions correspond to lat x lon x time, the simplest way to get an 86x1 array of ...

8 days ago | 1

| accepted

Better “centerpoint” than centroid of a concave polygon

I added a polycenter function to do exactly what you need in the Climate Data Toolbox for Matlab. If you have a shapefile, the...

11 days ago | 0

What should go in a next-generation MATLAB X?

If I could design Matlab from scratch I'd get rid of semicolons to suppress output, and make element-wise operations the def...

13 days ago | 0

What should go in a next-generation MATLAB X?

I'd like to define ranges using square brackets for inclusive and rounded brackets for exclusive. So insead of if x>=20 & x<30...

13 days ago | 0

How can I convert a shapefile boundaries to lat and lon?

If it's a standard map projection, use projinv.

14 days ago | 0

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How to find a figure's centroid inside a polyshape?

Also answered here, but reposting my answer in case anyone stumbles upon this thread. I just ran into this problem when trying...

14 days ago | 0

Better “centerpoint” than centroid of a concave polygon

I just ran into this problem when trying to place a text label in the middle of a crescent-shaped ice shelf. The centroid or the...

14 days ago | 0

Stereographic plot of Sea Surface Temperature Data around Antarctica.

Hi Ravi, There are a couple of ways to do this. Here's one way: Turn your vectors of latitude,longitude coordinates into 2D ...

29 days ago | 0

plot using latitude and longitude

That looks like you have scattered data. If you have an array of latitudes, an array of longitudes, and a corresponding array of...

5 months ago | 0

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polybuffer distance in meters?

I think you've got it right, Alex, but this calls for an explanation of the phrase numeric scalar. The word numeric just means a...

5 months ago | 1

| accepted

ploting 2d graph of a vector

You've pretty much got it, but you'll need to define a range of t values, and a value for the constants A, and B. You also need ...

5 months ago | 0

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Specific color corresponding to specific data using contourf colormap

Perhaps @Kelly Kearney's contourfcmap is what you need?

5 months ago | 0

Make a vector plot of the velocity field in polar coordinates

Can you use cart2pol to convert the coordinates and vector components to polar coordinates?

6 months ago | 0

Why ?? Undefined function 'crosscorr' for input arguments of type 'double'.

crosscorr is part of the econ toolbox. If you don't have that toolbox, you can probably rewrite your code to use xcorr instead. ...

6 months ago | 0

Fit data recorded with different internal clocks

This is an interesting problem. If you can identify a few peaks that occur throughout the 600 s measurement, and those peaks are...

6 months ago | 0

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How to create map with [x;y] coordinates? Mapping toolbox

No guaratees on the accuracy of the attached functions, but you may be able to convert between lat,lon and x,y using the attache...

6 months ago | 0

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How can i solve for this issue with the logical flow

I think the error is here: term3=q(i-1)*((r(i)-dr)/r(i)*dr); The first time through the loop, i=1, meaning i-1=0. There is no...

6 months ago | 0

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Adding line change the size of the image

Can you get the axis limits before plotting the lines, and then set the axis back to those limits afterwards? Something like thi...

6 months ago | 0

Color along line in polaraxes

What if you interpolate along a dense line and plot with polarscatter? I'm thinking something like this: theta = linspace(0,...

6 months ago | 0

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How to make a surface plot of imported data of a numerical function z=f(x,y)

Just to be clear, you already have the data, and it takes this form M = [x y z]; where x, y, and z are columns? My next qu...

6 months ago | 0

time position in graphic

This question is pretty vague, but here's pi displayed at the bottom right corner of a plot: txt = text(1,0,num2str(pi,'%4i'),...

6 months ago | 1

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I have a climatic dataset of a region where I am calculating time series (for drought index). The dimension of the dataset is 164*153*1416 (1416 months in the dataset and the others are the location). How I can average this over space and time?

To get a map of average SPEI, SPEI_mean = mean(SPEI,3,'omitnan'); and that calculates the mean along the third dimension (ti...

6 months ago | 0

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Antarctic Mapping Tool: how can I evaluate the distance of a point from the coastline?

The easiest solution is the dist2mask function in the Antarctic boundaries add-on for AMT. Syntax is d = dist2mask('openocean'...

6 months ago | 0

How to mask a 3-D raster using a multiple feature attribute shapefile?

Try this: mask = inpolygon(X,Y,[roi.X],[roi.Y]); You don't even need to remove the trailing nans. :)

6 months ago | 0

how to turn netcdf into contour map

Hi Abigail, The first thing I do with a netcdf file is type ncdisp('myfile.nc') to see what's inside it. If you have some ...

6 months ago | 0

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Extracting data from matrix

To only plot the ocean data, try masking out the land data by setting those values in A to NaN. like this: A(B==1) = NaN; % se...

6 months ago | 0

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Equal Sized random assortment, using randi?

This would be one way to define how many ones and how many twos in each column before randomizing them: N_cols = 8; % number o...

6 months ago | 0

PCA Graph of Data Comes Up Blank

I think you're mixing and matching different ways of defining filenames. As a result, dir is unable to find the files you're loo...

6 months ago | 0

datestr generating different string

How about myy = 2014; mym = 1; myd = 20; datestr(datenum(myy,mym,myd),'dd/mm/yyyy')

6 months ago | 0

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Three column table into matrix

I think table2array is the function you're looking for.

6 months ago | 1