Showing z value as an annotation when z value is >0.85 Tripcolor Matplotlib

问题

I have problem similar to tripcolor demo example. I have lon,lat , z values which i am plotting using Tripcolor i want to show annotation as lon value,lat value and z value at particular lon,lat location if my z value is less than 0.70.

For Example in below code , i want an annotation / popup message show in my plot which show lon value, lat value and z value at location lon=-2 lat=55 show annotation if z value is less than 0.70 i.e if zvalue is greater than 0.70 then in plot show me lon value lat value and zvalue.I want plot similar to the image provided. Thank you.

xy = np.asarray([
[-0.101, 0.872], [-0.080, 0.883], [-0.069, 0.888], [-0.054, 0.890],
[-0.045, 0.897], [-0.057, 0.895], [-0.073, 0.900], [-0.087, 0.898],
[-0.090, 0.904], [-0.069, 0.907], [-0.069, 0.921], [-0.080, 0.919],
[-0.073, 0.928], [-0.052, 0.930], [-0.048, 0.942], [-0.062, 0.949],
[-0.054, 0.958], [-0.069, 0.954], [-0.087, 0.952], [-0.087, 0.959],
[-0.080, 0.966], [-0.085, 0.973], [-0.087, 0.965], [-0.097, 0.965],
[-0.097, 0.975], [-0.092, 0.984], [-0.101, 0.980], [-0.108, 0.980],
[-0.104, 0.987], [-0.102, 0.993], [-0.115, 1.001], [-0.099, 0.996],
[-0.101, 1.007], [-0.090, 1.010], [-0.087, 1.021], [-0.069, 1.021],
[-0.052, 1.022], [-0.052, 1.017], [-0.069, 1.010], [-0.064, 1.005],
[-0.048, 1.005], [-0.031, 1.005], [-0.031, 0.996], [-0.040, 0.987],
[-0.045, 0.980], [-0.052, 0.975], [-0.040, 0.973], [-0.026, 0.968],
[-0.020, 0.954], [-0.006, 0.947], [ 0.003, 0.935], [ 0.006, 0.926],
[ 0.005, 0.921], [ 0.022, 0.923], [ 0.033, 0.912], [ 0.029, 0.905],
[ 0.017, 0.900], [ 0.012, 0.895], [ 0.027, 0.893], [ 0.019, 0.886],
[ 0.001, 0.883], [-0.012, 0.884], [-0.029, 0.883], [-0.038, 0.879],
[-0.057, 0.881], [-0.062, 0.876], [-0.078, 0.876], [-0.087, 0.872],
[-0.030, 0.907], [-0.007, 0.905], [-0.057, 0.916], [-0.025, 0.933],
[-0.077, 0.990], [-0.059, 0.993]])
x, y = np.rad2deg(xy).T

triangles = np.asarray([
[67, 66,  1], [65,  2, 66], [ 1, 66,  2], [64,  2, 65], [63,  3, 64],
[60, 59, 57], [ 2, 64,  3], [ 3, 63,  4], [ 0, 67,  1], [62,  4, 63],
[57, 59, 56], [59, 58, 56], [61, 60, 69], [57, 69, 60], [ 4, 62, 68],
[ 6,  5,  9], [61, 68, 62], [69, 68, 61], [ 9,  5, 70], [ 6,  8,  7],
[ 4, 70,  5], [ 8,  6,  9], [56, 69, 57], [69, 56, 52], [70, 10,  9],
[54, 53, 55], [56, 55, 53], [68, 70,  4], [52, 56, 53], [11, 10, 12],
[69, 71, 68], [68, 13, 70], [10, 70, 13], [51, 50, 52], [13, 68, 71],
[52, 71, 69], [12, 10, 13], [71, 52, 50], [71, 14, 13], [50, 49, 71],
[49, 48, 71], [14, 16, 15], [14, 71, 48], [17, 19, 18], [17, 20, 19],
[48, 16, 14], [48, 47, 16], [47, 46, 16], [16, 46, 45], [23, 22, 24],
[21, 24, 22], [17, 16, 45], [20, 17, 45], [21, 25, 24], [27, 26, 28],
[20, 72, 21], [25, 21, 72], [45, 72, 20], [25, 28, 26], [44, 73, 45],
[72, 45, 73], [28, 25, 29], [29, 25, 31], [43, 73, 44], [73, 43, 40],
[72, 73, 39], [72, 31, 25], [42, 40, 43], [31, 30, 29], [39, 73, 40],
[42, 41, 40], [72, 33, 31], [32, 31, 33], [39, 38, 72], [33, 72, 38],
[33, 38, 34], [37, 35, 38], [34, 38, 35], [35, 37, 36]])

 xmid = x[triangles].mean(axis=1)
 ymid = y[triangles].mean(axis=1)
 x0 = -5
 y0 = 52
zfaces = np.exp(-0.01 * ((xmid - x0) * (xmid - x0) +
                     (ymid - y0) * (ymid - y0)))
fig3, ax3 = plt.subplots()
ax3.set_aspect('equal')
tpc = ax3.tripcolor(x, y, triangles, facecolors=zfaces, edgecolors='k')
fig3.colorbar(tpc)
ax3.set_title('tripcolor of user-specified triangulation')
ax3.set_xlabel('Longitude (degrees)')
ax3.set_ylabel('Latitude (degrees)')
plt.show()

enter image description here #final image link

回答1:

Voila, but in my opinion, you are trying to annotate way too much.

Adding the following snippet, yields the image below:

indices, = np.where(zfaces > 0.8)
for idx in indices:
    xx, yy, zz = xmid[idx], ymid[idx], zfaces[idx]
    ax3.annotate(f'x={xx:.2f}\ny={yy:.2f}\nz={zz:.2f}', (xx, yy),
                 horizontalalignment='center',
                 verticalalignment='center',
                 fontsize='xx-small',
                 color='black')

Here is a slightly better option:

indices, = np.where(zfaces > 0.8)
for idx in indices:
    xx, yy, zz = xmid[idx], ymid[idx], zfaces[idx]
    ax3.annotate(f'{zz:.2f}', (xx, yy),
                 horizontalalignment='center',
                 verticalalignment='center',
                 fontsize='xx-small',
                 color='white')

来源：https://stackoverflow.com/questions/59246874/showing-z-value-as-an-annotation-when-z-value-is-0-85-tripcolor-matplotlib