Add/Remove items from existing Markers

This example shows how to add or remove marker from an existing collection. This is done by setting the parameters (offsets, sizes, etc.) of the collection.

Create a signal

import hyperspy.api as hs
import numpy as np

# Create a Signal2D with 2 navigation dimensions
rng = np.random.default_rng(0)
data = np.arange(15*100*100).reshape((15, 100, 100))
s = hs.signals.Signal2D(data)

Create text marker

# Define the position of the texts
offsets = np.stack([np.arange(0, 100, 10)]*2).T + np.array([5,]*2)
texts = np.array(['a', 'b', 'c', 'd', 'e', 'f', 'g', 'f', 'h', 'i'])

m = hs.plot.markers.Texts(
    offsets=offsets,
    texts=texts,
    sizes=3,
    )

print(f'Number of markers is {len(m)}.')

s.plot()
s.add_marker(m)

• 
• 

Number of markers is 10.

Remove the last text of the collection

# Set new texts and offsets parameters with one less item
m.remove_items(indices=-1)

print(f'Number of markers is {len(m)} after removing one marker.')

s.plot()
s.add_marker(m)

• 
• 

Number of markers is 9 after removing one marker.

Add another text of the collection

# Define the position in the middle of the axes

m.add_items(offsets=np.array([[50, 50]]), texts=np.array(["new text"]))

print(f'Number of markers is {len(m)} after adding the text {texts[-1]}.')

s.plot()
s.add_marker(m)

• 
• 

Number of markers is 10 after adding the text i.

sphinx_gallery_thumbnail_number = 2