[Matplotlib-users] 2D array plot picking explicit values to colour and legend
Dear matplotlib-users, I have a spatial data set that has coded values for each cell, which are limited to just a few numbers, ie -, 0, 100, and . I would like to display this data with a plot similar to pcolor, but I don't want a colorbar, I want a legend showing the colors for each code and an explanation for what each code represents. I would like to be able to choose a subset of the codes as well, for example just plotting the 0 and 100 codes and ignoring the - and codes. I have seen a few similar attempts that used BoundaryNorm, but I don't want to show a range of values I just want to set colors for a few explicit values. Those examples also had a colorbar and, as I said, I would prefer a legend. Can anyone offer any tips? Thanks Mat -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336. -- For Developers, A Lot Can Happen In A Second. Boundary is the first to Know...and Tell You. Monitor Your Applications in Ultra-Fine Resolution. Try it FREE! http://p.sf.net/sfu/Boundary-d2dvs2 ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] 2D array plot picking explicit values to colour and legend
On 04/09/2012 02:22 AM, Mathew Topper wrote: Dear matplotlib-users, I have a spatial data set that has coded values for each cell, which are limited to just a few numbers, ie -, 0, 100, and . I would like to display this data with a plot similar to pcolor, but I don't want a colorbar, I want a legend showing the colors for each code and an explanation for what each code represents. I would like to be able to choose a subset of the codes as well, for example just plotting the 0 and 100 codes and ignoring the - and codes. I have seen a few similar attempts that used BoundaryNorm, but I don't want to show a range of values I just want to set colors for a few explicit values. Those examples also had a colorbar and, as I said, I would prefer a legend. Can anyone offer any tips? For the plot itself you can use pcolor if your data are on a quadrilateral grid, or a PathCollection or PolyCollection otherwise. For the legend, you can use proxy artists: http://matplotlib.sourceforge.net/users/legend_guide.html#using-proxy-artist Eric Thanks Mat -- For Developers, A Lot Can Happen In A Second. Boundary is the first to Know...and Tell You. Monitor Your Applications in Ultra-Fine Resolution. Try it FREE! http://p.sf.net/sfu/Boundary-d2dvs2 ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] 2D array plot picking explicit values to colour and legend
Hi Eric, thanks for the tip about the legend. Regarding the data, assuming i am using pcolor, am I right in thinking that using Boundarynorm would be the best way to control the colors for each code? Thanks Mat On 04/09/2012 06:26 PM, Eric Firing wrote: On 04/09/2012 02:22 AM, Mathew Topper wrote: Dear matplotlib-users, I have a spatial data set that has coded values for each cell, which are limited to just a few numbers, ie -, 0, 100, and . I would like to display this data with a plot similar to pcolor, but I don't want a colorbar, I want a legend showing the colors for each code and an explanation for what each code represents. I would like to be able to choose a subset of the codes as well, for example just plotting the 0 and 100 codes and ignoring the - and codes. I have seen a few similar attempts that used BoundaryNorm, but I don't want to show a range of values I just want to set colors for a few explicit values. Those examples also had a colorbar and, as I said, I would prefer a legend. Can anyone offer any tips? For the plot itself you can use pcolor if your data are on a quadrilateral grid, or a PathCollection or PolyCollection otherwise. For the legend, you can use proxy artists: http://matplotlib.sourceforge.net/users/legend_guide.html#using-proxy-artist Eric Thanks Mat -- For Developers, A Lot Can Happen In A Second. Boundary is the first to Know...and Tell You. Monitor Your Applications in Ultra-Fine Resolution. Try it FREE! http://p.sf.net/sfu/Boundary-d2dvs2 ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users -- Dr. Mathew Topper Institute for Energy Systems School of Engineering The University of Edinburgh Faraday Building The King's Buildings Edinburgh EH9 3JL Tel: +44 (0)131 650 5570 School fax: +44 (0)131 650 6554 mathew.top...@ed.ac.uk mailto:mathew.top...@ed.ac.uk http://www.see.ed.ac.uk http://www.see.ed.ac.uk/ The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336. -- For Developers, A Lot Can Happen In A Second. Boundary is the first to Know...and Tell You. Monitor Your Applications in Ultra-Fine Resolution. Try it FREE! http://p.sf.net/sfu/Boundary-d2dvs2 ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] 2D array plot picking explicit values to colour and legend
On 04/09/2012 08:17 AM, Mathew Topper wrote: Hi Eric, thanks for the tip about the legend. Regarding the data, assuming i am using pcolor, am I right in thinking that using Boundarynorm would be the best way to control the colors for each code? Mat, I think BoundaryNorm is overkill and/or awkward for your case. It sounds like you don't have ordinary values, but rather a set of labels that happen to be integers. I would use a ListedColormap and then use sequential integers as the C values to index directly into the colormap: C = np.array([[0,1,2],[2,0,1]]) import matplotlib.colors as mcolors cmap = mcolors.ListedColormap(['r', 'g', 'lightgray']) pcolor(C, cmap=cmap, norm=mcolors.NoNorm()) Of course you would need to map your sequence of numbers (-, 0, ...) to a sequence of integers starting at zero. The key point is that the NoNorm() instance leaves your original C values alone, and since they are integers, they are then used directly as indices. You could also make your own mcolors.Normalize subclass which would process your labels and return either a float in the 0-1 range, or an integer for direct indexing. When you need only a very few colors, the ListedColormap with direct indexing is nice because it allows you to specify those colors using any valid color specification method. Eric Thanks Mat On 04/09/2012 06:26 PM, Eric Firing wrote: On 04/09/2012 02:22 AM, Mathew Topper wrote: Dear matplotlib-users, I have a spatial data set that has coded values for each cell, which are limited to just a few numbers, ie -, 0, 100, and . I would like to display this data with a plot similar to pcolor, but I don't want a colorbar, I want a legend showing the colors for each code and an explanation for what each code represents. I would like to be able to choose a subset of the codes as well, for example just plotting the 0 and 100 codes and ignoring the - and codes. I have seen a few similar attempts that used BoundaryNorm, but I don't want to show a range of values I just want to set colors for a few explicit values. Those examples also had a colorbar and, as I said, I would prefer a legend. Can anyone offer any tips? For the plot itself you can use pcolor if your data are on a quadrilateral grid, or a PathCollection or PolyCollection otherwise. For the legend, you can use proxy artists: http://matplotlib.sourceforge.net/users/legend_guide.html#using-proxy-artist Eric Thanks Mat -- For Developers, A Lot Can Happen In A Second. Boundary is the first to Know...and Tell You. Monitor Your Applications in Ultra-Fine Resolution. Try it FREE! http://p.sf.net/sfu/Boundary-d2dvs2 ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users -- Dr. Mathew Topper Institute for Energy Systems School of Engineering The University of Edinburgh Faraday Building The King’s Buildings Edinburgh EH9 3JL Tel: +44 (0)131 650 5570 School fax: +44 (0)131 650 6554 mathew.top...@ed.ac.uk mailto:mathew.top...@ed.ac.uk http://www.see.ed.ac.uk http://www.see.ed.ac.uk/ The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336. -- For Developers, A Lot Can Happen In A Second. Boundary is the first to Know...and Tell You. Monitor Your Applications in Ultra-Fine Resolution. Try it FREE! http://p.sf.net/sfu/Boundary-d2dvs2 ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users -- For Developers, A Lot Can Happen In A Second. Boundary is the first to Know...and Tell You. Monitor Your Applications in Ultra-Fine Resolution. Try it FREE! http://p.sf.net/sfu/Boundary-d2dvs2 ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
