Truncation

.gitignore

@@ -1 +1,10 @@
 *.pyc
+
+# general things to ignore
+build/
+dist/
+*.egg-info/
+*.egg
+*.py[cod]
+__pycache__/
+*.ipynb_checkpoints/

README.md

@@ -23,7 +23,8 @@ The library provides functions for plotting projected lines, curves (trajectorie
 <img src="/readme_images/rgba_example.png" width="150" height="150"/>
 <img src="/readme_images/various_lines.png" width="150" height="150"/>
 <img src="/readme_images/colored_trajectory.png" width="150" height="150"/>
-<img src="/readme_images/scatter.png" width="150" height="150"/><br/>
+<img src="/readme_images/scatter.png" width="150" height="150"/>
+<img src="/readme_images/truncation_all_corners.png" width="200" height="150"/><br/>
 <br/>
 <img src="/readme_images/btweinstein_example2.png" width="300" height="150"/>
 <img src="/readme_images/btweinstein_example.png" width="300" height="150"/>
@@ -394,6 +395,58 @@ do so automatically when you pass `clockwise=True` to `tax.ticks()`.
 There is a [more detailed discussion](https://github.com/marcharper/python-ternary/issues/18)
 on issue #18 (closed).
 
+# Custom Axis Data Limits
+
+By default, the axes limits are [0, scale] i.e. simplex coordinates but it is possible to set 
+custom data limits to the axes instead. This is done by passing a dict into set_axis_limits.
+The keys are b, l and r for the three axes and the values are a list of the min and max in 
+data coords for that axis. max-min for each axis is the same as the scale i.e. 9 in this case.
+
+```python
+tax.set_axis_limits({'b': [60, 75], 'l': [15, 30], 'r': [10, 25]})
+```
+
+This can be used to zoom in on a particular region, for example. Please see
+the [custom axis scaling example](examples/custom_axis_scaling.py) for further
+details.
+
+<p align="center">
+<img src="/readme_images/zoom_example.png" width="732" height="400"/>
+</p>
+
+# Truncated Simplex
+
+One or more corners can be removed from the simplex by setting a truncation. 
+This may be useful for saving whitespace if the data are grouped in one area
+of the plot. A truncation is specified in data coordinates by passing a dict
+into tax.set_truncation. The keys are two letters specifying the start and end
+axes of the truncation line and the values give the maximum of the first axis
+specified in data coordinates. For the example on the left below, we write:
+
+```python
+tax.set_truncation({'rl' : 8})
+```
+
+The result is that the truncation line has been drawn from the right axis at
+data coordinate 8 to the left axis, cutting off the top corner. As the figure is no 
+longer a triangle, we need to get and set custom axis ticks and tick labels. 
+There are convenience functions for this in the case of a truncation and/or 
+custom axis data limits. Again for the left image shown below:
+
+```python
+tax.get_ticks_from_axis_limits(multiple=2)
+offset=0.013
+tax.set_custom_ticks(fontsize=8, offset=offset,
+                     tick_formats="%.1f", linewidth=0.25)
+```
+
+<p align="center">
+<img src="/readme_images/truncation_top_corner.png" width="400" height="300"/>
+<img src="/readme_images/truncation_all_corners.png" width="314" height="236"/>
+</p>
+
+Please see the [truncated simplex example](examples/truncated_simplex_example.py) 
+for further details.
 
 # RGBA colors
 
@@ -463,6 +516,7 @@ contribute.
 - Bryan Weinstein [btweinstein](https://github.com/btweinstein): Hexagonal heatmaps, colored trajectory plots
 - [chebee7i](https://github.com/chebee7i): Docs and figures, triangular heatmapping
 - [Cory Simon](https://github.com/CorySimon): Axis Colors, colored heatmap example
+- [tgwoodcock](https://github.com/tgwoodcock): Custom axis data limits, truncated simplex
 
 # Known-Issues
 

examples/custom_axis_scaling.py

@@ -1,12 +1,24 @@
-import ternary
+"""
+This script gives two examples of setting custom axis data limits instead of
+having the axis limits being from 0 to scale as is the default case.
+
+In the first example we simply set some axis data limits, get and set the
+ticks for the axes and then scatter some data. This example is then repeated
+but with the additional feature of showing custom axis tick formatting.
+
+The second example shows how to use custom axis scaling to achieve a zoom
+effect. We draw the full plot on the left and then zoom into a specific
+region and plot that on the right. The basic principle is the same as the
+first example.
+"""
 
-# Simple example:
-## Boundary and Gridlines
-scale = 9
-figure, tax = ternary.figure(scale=scale)
+import ternary
 
+## Simple example:
+figure, tax = ternary.figure(scale=9)
+figure.set_size_inches((4.8,4.8))
+figure.subplots_adjust(left=0.05, right=0.95, bottom=0.05, top=0.95)
 tax.ax.axis("off")
-figure.set_facecolor('w')
 
 # Draw Boundary and Gridlines
 tax.boundary(linewidth=1.0)
@@ -19,10 +31,10 @@
 tax.bottom_axis_label("Hogs", fontsize=fontsize, offset=0.06)
 
 
-# Set custom axis limits by passing a dict into set_limits.
-# The keys are b, l and r for the three axes and the vals are a list
+# Set custom axis DATA limits by passing a dict into set_axis_limits.
+# The keys are b, l and r for the three axes and the values are a list
 # of the min and max in data coords for that axis. max-min for each
-# axis must be the same as the scale i.e. 9 in this case.
+# axis is the same as the scale i.e. 9 in this case.
 tax.set_axis_limits({'b': [67, 76], 'l': [24, 33], 'r': [0, 9]})
 # get and set the custom ticks:
 tax.get_ticks_from_axis_limits()
@@ -35,15 +47,14 @@
 
 tax.ax.set_aspect('equal', adjustable='box')
 tax._redraw_labels()
+figure.canvas.draw()
 
 
 ## Simple example with axis tick formatting:
-## Boundary and Gridlines
-scale = 9
-figure, tax = ternary.figure(scale=scale)
-
+figure, tax = ternary.figure(scale=9)
+figure.set_size_inches((4.8,4.8))
+figure.subplots_adjust(left=0.05, right=0.95, bottom=0.05, top=0.95)
 tax.ax.axis("off")
-figure.set_facecolor('w')
 
 # Draw Boundary and Gridlines
 tax.boundary(linewidth=1.0)
@@ -55,33 +66,34 @@
 tax.right_axis_label("Dogs", fontsize=fontsize, offset=0.12)
 tax.bottom_axis_label("Hogs", fontsize=fontsize, offset=0.06)
 
-
-# Set custom axis limits by passing a dict into set_limits.
-# The keys are b, l and r for the three axes and the vals are a list
+# Set custom axis DATA limits by passing a dict into set_axis_limits.
+# The keys are b, l and r for the three axes and the values are a list
 # of the min and max in data coords for that axis. max-min for each
-# axis must be the same as the scale i.e. 9 in this case.
+# axis is the same as the scale i.e. 9 in this case.
 tax.set_axis_limits({'b': [67, 76], 'l': [24, 33], 'r': [0, 9]})
+
 # get and set the custom ticks:
 # custom tick formats:
 # tick_formats can either be a dict, like below or a single format string
 # e.g. "%.3e" (valid for all 3 axes) or None, in which case, ints are
 # plotted for all 3 axes.
 tick_formats = {'b': "%.2f", 'r': "%d", 'l': "%.1f"}
-
 tax.get_ticks_from_axis_limits()
 tax.set_custom_ticks(fontsize=10, offset=0.02, tick_formats=tick_formats)
 
 # data can be plotted by entering data coords (rather than simplex coords):
 points = [(70, 3, 27), (73, 2, 25), (68, 6, 26)]
-points_c = tax.convert_coordinates(points,axisorder='brl')
+points_c = tax.convert_coordinates(points, axisorder='brl')
 tax.scatter(points_c, marker='o', s=25, c='r')
 
 tax.ax.set_aspect('equal', adjustable='box')
 tax._redraw_labels()
+figure.canvas.draw()
+
 
 ## Zoom example:
-## Draw a plot with the full range on the left and a second plot which
-## shows a zoomed region of the left plot.
+# Draw a plot with the full range on the left and a second plot which
+# shows a zoomed region of the left plot.
 fig = ternary.plt.figure(figsize=(11, 6))
 ax1 = fig.add_subplot(2, 1, 1)
 ax2 = fig.add_subplot(2, 1, 2)
@@ -114,8 +126,8 @@
 tax2.set_axis_limits({'b': [60, 75], 'l': [15, 30], 'r': [10, 25]})
 tax2.get_ticks_from_axis_limits(multiple=5)
 tick_formats = "%.1f"
-tax2.set_custom_ticks(fontsize=10, offset=0.025, multiple=5,
-                      axes_colors=axes_colors, tick_formats=tick_formats)
+tax2.set_custom_ticks(fontsize=10, offset=0.025, axes_colors=axes_colors,
+                      tick_formats=tick_formats)
 
 # plot some data
 points = [(62, 12, 26), (63.5, 13.5, 23), (65, 14, 21), (61, 15, 24),
@@ -132,11 +144,10 @@
 tax1.line((60, 10, 30), (60, 25, 15), color='r', lw=2.0)
 tax1.line((75, 10, 15), (60, 25, 15), color='r', lw=2.0)
 
-fig.set_facecolor("w")
-
 tax1.ax.set_position([0.01, 0.05, 0.46, 0.8])
 tax2.ax.set_position([0.50, 0.05, 0.46, 0.8])
 
 tax1.resize_drawing_canvas()
 tax2.resize_drawing_canvas()
+figure.canvas.draw()
 ternary.plt.show()

examples/truncated_simplex_example.py

@@ -0,0 +1,139 @@
+"""
+This script gives two examples of truncation i.e. cutting one
+or more corners off the simplex to save whitespace in a figure.
+
+The first example is simple: only the top corner is truncated and the data
+coordainates are the same as the simplex coordinates.
+
+The second example is more complex: all three corners have been truncated
+and we set axis data limits which are not the same as the simplex coords.
+"""
+
+import ternary
+
+## Simple example with the top corner truncated
+scale = 10
+figure, tax = ternary.figure(scale=scale)
+figure.subplots_adjust(left=-0.1, right=1.1, bottom=0.1, top=1.1)
+tax.set_truncation({'rl' : 8})
+tax.ax.axis("off")
+
+
+# Draw Boundary and Gridlines
+tax.boundary(linewidth=0.25)
+tax.gridlines(color="black", multiple=1, linewidth=0.25, ls='-')
+
+
+# Set Axis labels
+tax.left_axis_label(r"$\longleftarrow$ Hogs", fontsize=10)
+tax.right_axis_label(r"$\longleftarrow$ Dogs", fontsize=10)
+tax.bottom_axis_label(r"Logs $\longrightarrow$", fontsize=10, offset=0.08)
+
+
+# As we have set a truncation, we need to get and set custom ticks
+tax.get_ticks_from_axis_limits(multiple=2)
+offset=0.013
+tax.set_custom_ticks(fontsize=8, offset=offset,
+                     tick_formats="%.1f", linewidth=0.25)
+# here we have used a tick formatting string to label all the axes with
+# floats to one decimal place.
+
+tax.ax.axis("scaled")
+tax._redraw_labels()
+figure.canvas.draw()
+
+
+
+
+
+
+
+## More complex example with truncations on all 3 corners of the simplex
+## and axes with data coordinates which are different to simplex coordinates.
+scale = 14
+figure, tax = ternary.figure(scale=scale)
+w_i,h_i = 3.15, 2.36
+figure.set_size_inches((w_i,h_i))
+figure.set_dpi(150)
+tax.ax.axis("off")
+figure.subplots_adjust(left=0, right=1, bottom=0, top=1)
+
+# here we set the data limits of the axes (of the complete simplex)
+tax.set_axis_limits({'b' : [52, 59], 'r' : [0, 7], 'l' : [41, 48]})
+
+# now we set the truncation of all 3 corners in data coords. The truncation
+# point refers to the first axis in the key e.g. "b" will be cut off at 57.5
+# parallel to the left axis until we reach the "r" axis for "br" : 57.5
+tax.set_truncation({'br' : 57.5, 'rl' : 4, 'lb' : 46.5})
+
+# Draw Boundary and Gridlines
+tax.boundary(linewidth=0.25)
+tax.gridlines(color="black", multiple=1, linewidth=0.25, ls='-')
+
+# As the truncated figure is no longer a triangle, we need to set custom
+# positions for the axis labels. One way is to enter positions as 2-tuples
+# in xy data coords (e.g. obtained interactively by the hovering the mouse
+# over the matplotlib figure axes) and convert them to simplex coords
+# (3-tuples) for plotting:
+qs = {"l" : (1.94, 5.80),
+      "b" : (6.67, -1.5),
+      "r" : (12.34, 5.58)
+      }
+
+pos = {i : ternary.helpers.planar_to_coordinates(j, tax._scale).tolist()
+        for i, j in qs.items()
+        }
+
+fontsize = 10
+tax.left_axis_label(r"$\longleftarrow$ Hogs", position=pos["l"],
+                    fontsize=fontsize)
+tax.right_axis_label(r"$\longleftarrow$ Dogs", position=pos["r"],
+                      fontsize=fontsize)
+tax.bottom_axis_label(r"Logs $\longrightarrow$", position=pos["b"],
+                      fontsize=fontsize)
+
+
+# We also need to set custom ticks for this example.
+# We could use tax.get_ticks_from_axis_limits(multiple=1) and this gives
+# us all the ticks on the remaining visible parts of the simplex boundary.
+# Instead we show here how to plot specific ticks.
+# define ticks in data coords along each axis:
+tax._ticks = {'b' : [54,55,56,57],
+              'r' : [2,3,4],
+              'l' : [44,45,46]}
+# define tick locations along each axis in simplex coords:
+tax._ticklocs = {'b' : [4,6,8,10],
+                  'r' : [4,6,8],
+                  'l' : [4,6,8]}
+
+offset=0.013
+tax.set_custom_ticks(fontsize=8, offset=offset, tick_formats="%i",
+                      linewidth=0.25)
+
+# As we have applied a truncation, it can be helpful to plot extra
+# ticks which are not located on the simplex boundary. We specify
+# which axis the tick belongs to so that the tick can be drawn with
+# the correct orientation: horizontal, right parallel or left parallel.
+# Then give the position of the tick in simplex coordinates and specify
+# the tick label as a string in data coordinates:
+tax.add_extra_tick('r', (11,2,1), offset, '1', fontsize=8, color='k',
+                    linewidth=0.25)
+tax.add_extra_tick('r', (11,0,3), offset, '0', fontsize=8, color='k',
+                    linewidth=0.25)
+
+tax.add_extra_tick('l', (2,8,4), offset, '43', fontsize=8, color='k',
+                    linewidth=0.25)
+tax.add_extra_tick('l', (4,8,2), offset, '42', fontsize=8, color='k',
+                    linewidth=0.25)
+tax.add_extra_tick('l', (6,8,0), offset, '41', fontsize=8, color='k',
+                    linewidth=0.25)
+
+tax.add_extra_tick('b', (2,1,11), offset, '53', fontsize=8, color='k',
+                    linewidth=0.25)
+
+
+tax.ax.axis("scaled")
+tax.ax.axis([0, 14, -2, 9])
+tax._redraw_labels()
+
+ternary.plt.show()

ternary/colormapping.py

@@ -91,7 +91,7 @@ def colorbar_hack(ax, vmin, vmax, cmap, scientific=False, cbarlabel=None, norm=N
     if norm is None:
         norm = plt.Normalize(vmin=vmin, vmax=vmax)
     sm = plt.cm.ScalarMappable(cmap=cmap, norm=norm)
-    sm._A = []
+    sm.set_array(None)
     cb = plt.colorbar(sm, ax=ax, **kwargs)
     if cbarlabel is not None:
         cb.set_label(cbarlabel)