MATLAB for Visualization

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1. To display a new graph on on top of an old one, you can use command hold on. In this way, you can create multiple plots in a same window. Though plot can already do multiple plot, command hold on can be very useful when you want to add some new points or curves to an existing graph (e.g. a histogram).

2. Function subplot displays multiple plots in the same window, which is similar to settings par(mfrow=c(2,2)) or par(mfcol=c(2,3)) in R.

3. Function hist and histc produces histograms.

4. Function staris produces step graph.

5. Function plot plots 2-D graph while function surf plots 3-D graphs. Function surf is usually used in conjugate with function meshgrid which can create a matrix of points over which the surface is to be plotted. You can also use ndgrid instead of meshgrid to generate a matrix of points. However, ndgrid is usually higher dimensions and the usage is a little different from meshgrid, so you have to be careful if you wan to use it.

6. After plotting figures using plot, you can use title to add titles for the figures, axis to set configurations for the axies, and xlabel and ylabel to set labels for the x and y axes. You can also use set to set all configurations for the plots. To do this, you have to first get the handle of the elements in the plots that you want to modify, and then apply set on it.

7. inpolygon can check whether given points are inside a polygon or not.

8. spy visualizes sparse matrices.

9. image can not only display images but also make mosaic plot (sometimes called heat plot or level plot) of a matrices. For example, to show the mosaic plot of matrix x, you can use image(x,'CDataMap','CDataMapping','scaled').