cell2nancat documentation

The cell2nancat function concatenates elements of a cell into a NaN-separated vector.

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Syntax

xv = cell2nancat(xc)
[xv,yv,...,zv] = cell2nancat(xc,yc,...,zc)

Description

xv = cell2nancat(xc) concatenates the numeric arrays of cell array xc into a single vector separated by NaNs.

[xv,yv,...,zv] = cell2nancat(xc,yc,...,zc) as above but for any number of cell arrays.

Example

CDT comes with data for all the national and US states boundaries. Here's the format it's in:

load borderdata
whos % prints name & size of each variable in workspace

  Name          Size              Bytes  Class     Attributes

  GEOM          1x4                  32  double              
  clat        302x1               36240  cell                
  clon        302x1               36240  cell                
  lat         302x1             4629240  cell                
  lon         302x1             4629240  cell                
  places      302x1               40192  cell                

Thos are all cell arrays. Each of those 302 arrays contains the borders of a different state or country. To see what that looks like, here are the names and latitudes of the first three countries:

[places(1:3) lat(1:3)]

ans =
  3×2 cell array
    {'Antigua and Barbuda'}    {1×50   double}
    {'Algeria'            }    {1×1242 double}
    {'Azerbaijan'         }    {1×876  double}

If you want to plot all the borderlines, your first inclination might be to loop through each of the 302 entries and plot them individually, like this:

hold on
for k = 1:302
   plot(lon{k},lat{k})
end

However, looping is computationally slow and you might not want 300+ different objects plotted in your figure. So instead, you can turn each cell array into a vector and plot everything together.

Here's how cell2nancat works: Give it a cell array, and get a vector in return:

latv = cell2nancat(lat);

whos lat latv

  Name           Size              Bytes  Class     Attributes

  lat          302x1             4629240  cell                
  latv      574729x1             4597832  double              

Now that 302x1 cell array has been turned into a 574729x1 vector array containing all the borderlines from lat. To use the function on multiple cell arrays, just enter them all into cell2nancat:

[latv,lonv,clatv,clonv] = cell2nancat(lat,lon,clat,clon);

plot(lonv,latv,'b') % blue borderlines
hold on
plot(clonv,clatv,'r.') % landmass centroids as red dots

Author Info

This function is part of the Climate Data Toolbox for Matlab. The function and supporting documentation were written by Chad A. Greene of the University of Texas at Austin.

Published with MATLAB® R2018b