Working with contours

The madcubapy.regions package also helps the user select regions by using contour levels from maps.

The select_contour_regions() function plots a ContourSet object in a pop-up window and lets the user select different closed contours in the map via mouse clicks.

When the user selects the ‘Save and exit’ button the window closes and the function returns the indexes of the selected regions. These indexes can be used to import that region as a Patch or ContourSet object using the import_region_patch() and import_region_contourset() respectively. Both functions accept kwargs that are passed to the creation of the Patch and ContourSet objects.

The function will plot the input contour in a blank space if no other input parameters are set. To plot the contour on top of a map the user has to provide a second input parameter:

• A previously plotted Figure, Axes, or WCSAxes objects throgh the fig or ax parameters.

• A MadcubaMap or CCDData objects through the fitsmap parameter.

Example

# Read map
>>> madcuba_map = MadcubaMap.read("example_map.fits")

# Plot the map
>>> fig = plt.figure(figsize=(6,6))
>>> ax, img = add_wcs_axes(fig, 1, 1, 1, fitsmap=madcuba_map)

# Create the contour
>>> contour_level = 15
>>> contour = ax.contour(madcuba_map.data[0, 0, :, :], [contour_level],
                         origin=None, colors=['white'], linewidths=1)

# Possible ways of getting region indexes
>>> region_index = select_contour_regions(contour_set)
>>> region_index = select_contour_regions(contour_set, fig=fig)
>>> region_index = select_contour_regions(contour_set, ax=ax)
>>> region_index = select_contour_regions(contour_set, fitsmap=madcuba_map)

# Get a specific region as a a contourset object
>>> region_contour = import_region_contourset(ax, contour, index=region_index,
                                              colors='black',
                                              linewidths=[1], linestyles='--')

# Get a specific region as a a patch object
>>> region_patch = import_region_patch(ax, contour, index=region_index,
                                       color='white', lw=3)
>>> ax.add_patch(region_patch)