Non-uniform contourf/imagesc/co​lorbar

This function allows non-uniform contour levels contourf/imagesc/pcolor.
Updated 11 Sep 2018

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The colormap in Matlab supports only linear mapping, which is inconvenient when plotting data spaning multiple orders, e.g., peaks(100).^4. This function uses the trick of piecewise-linearly mapping to allow non-uniform contour levels contourf/imagesc/pcolor.

--- Usage ---
varargout = contourfnu(x,y,data,v,cmap,pos_colorbar,overticklabel,method,ninterp,nancolor)

--- Input Variables ---
x : x-coordinates of grid, vector or 2d matrix
y : y-coordinates of grid, vector or 2d matrix
If x and y are vectors, then length(x)==size(z,2) and length(y)==size(Z,1).
If x and y are 2d matrix, they are generated by meshgrid
data : 2d matrix to be ploted
v : vector of contour levels (default:linspace(datamin,datamax,10))
cmap : color map array (default:jet)
pos_colorbar : 'none', or location with respect to the axes (default:'eastoutside')
overticklabel : whether or not label the overrange ticks at colorbar (default:true)
method : imagesc, contourf, contour or pcolor (default:imagesc)
ninterp : repeatedly interp times in each dimension (default:0)
nancolor : axis backgroud color

--- Output Variable ---
hout : structure with handles
.h plot handle
.c contour matrix (method='contourf')
.hc colorbar handle (pos_colorbar~='none')

Cite As

Yuxin Jiang (2024). Non-uniform contourf/imagesc/colorbar (, MATLAB Central File Exchange. Retrieved .

MATLAB Release Compatibility
Created with R2017a
Compatible with any release
Platform Compatibility
Windows macOS Linux
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Version Published Release Notes

Add support for pcolor

Update demo and description.
Fix a bug when pos_colorbar='southourside', 'northourside', 'south' or 'north'.
Add support for inf in v. This is useful for common colorbar plots.

handle Inf(s)

handle NaNs

add a parameter to control the max/min ticklabel(s)
update demo
update comments

update description