~marvin.utils.general.maskbit.Maskbit contains the schema for a MaNGA flag (e.g., MANGA_DAPPIXMASK) and provides convenience functions for translating amongst mask values, bits, and labels.
~marvin.utils.general.maskbit.Maskbit is most frequently encountered as an attribute on a marvin-tools object (e.g., marvin.tools.quantities.Map.pixmask is an instance of ~marvin.utils.general.maskbit.Maskbit).
from marvin.tools.maps import Maps
maps = Maps(plateifu='8485-1901')
ha = maps['gflux ha']
ha.pixmask
# <Maskbit 'MANGA_DAPPIXMASK'
#
# bit label description
# 0 0 NOCOV No coverage in this spaxel
# 1 1 LOWCOV Low coverage in this spaxel
# 2 2 DEADFIBER Major contributing fiber is dead
# 3 3 FORESTAR Foreground star
# 4 4 NOVALUE Spaxel was not fit because it did not meet sel...
# 5 5 UNRELIABLE Value is deemed unreliable; see TRM for defini...
# 6 6 MATHERROR Mathematical error in computing value
# 7 7 FITFAILED Attempted fit for property failed
# 8 8 NEARBOUND Fitted value is too near an imposed boundary; ...
# 9 9 NOCORRECTION Appropriate correction not available
# 10 10 MULTICOMP Multi-component velocity features present
# 11 30 DONOTUSE Do not use this spaxel for science>It is also possible to initialize a ~marvin.utils.general.maskbit.Maskbit instance without a marvin-tools object:
from marvin.utils.general.maskbit import Maskbit
mngtarg1 = Maskbit('MANGA_TARGET1')
mngtarg1.schema
# bit label description
# 0 0 NONE
# 1 1 PRIMARY_PLUS_COM March 2014 commissioning
# 2 2 SECONDARY_COM March 2014 commissioning
# 3 3 COLOR_ENHANCED_COM March 2014 commissioning
# 4 4 PRIMARY_v1_1_0 First tag, August 2014 plates
# 5 5 SECONDARY_v1_1_0 First tag, August 2014 plates
# 6 6 COLOR_ENHANCED_v1_1_0 First tag, August 2014 plates
# 7 7 PRIMARY_COM2 July 2014 commissioning
# 8 8 SECONDARY_COM2 July 2014 commissioning
# 9 9 COLOR_ENHANCED_COM2 July 2014 commissioning
# 10 10 PRIMARY_v1_2_0
# 11 11 SECONDARY_v1_2_0
# 12 12 COLOR_ENHANCED_v1_2_0
# 13 13 FILLER Filler targets
# 14 14 RETIRED Bit retired from use>~marvin.utils.general.maskbit.Maskbit makes properly applying masks easy by providing the schema for a flag:
from marvin.tools.maps import Maps
maps = Maps(plateifu='8485-1901')
ha = maps['gflux ha']
ha.manga_target1.description
# 'Targeting bits for all galaxy targets.'
ha.manga_target1.schema
# bit label description
# 0 0 NONE
# 1 1 PRIMARY_PLUS_COM March 2014 commissioning
# 2 2 SECONDARY_COM March 2014 commissioning
# 3 3 COLOR_ENHANCED_COM March 2014 commissioning
# 4 4 PRIMARY_v1_1_0 First tag, August 2014 plates
# 5 5 SECONDARY_v1_1_0 First tag, August 2014 plates
# 6 6 COLOR_ENHANCED_v1_1_0 First tag, August 2014 plates
# 7 7 PRIMARY_COM2 July 2014 commissioning
# 8 8 SECONDARY_COM2 July 2014 commissioning
# 9 9 COLOR_ENHANCED_COM2 July 2014 commissioning
# 10 10 PRIMARY_v1_2_0
# 11 11 SECONDARY_v1_2_0
# 12 12 COLOR_ENHANCED_v1_2_0
# 13 13 FILLER Filler targets
# 14 14 RETIRED Bit retired from useIt also contains the mask value, the corresponding bits, and the corresponding labels for the marvin-tools object:
ha.manga_target1.mask # 2336
ha.manga_target1.bits # [5, 8, 11]
ha.manga_target1.labels # ['SECONDARY_v1_1_0', 'SECONDARY_COM2', 'SECONDARY_v1_2_0']Let's look at a flag with a mask that is an array and not just a single integer:
ha.pixmask
# <Maskbit 'MANGA_DAPPIXMASK'
#
# bit label description
# 0 0 NOCOV No coverage in this spaxel
# 1 1 LOWCOV Low coverage in this spaxel
# 2 2 DEADFIBER Major contributing fiber is dead
# 3 3 FORESTAR Foreground star
# 4 4 NOVALUE Spaxel was not fit because it did not meet sel...
# 5 5 UNRELIABLE Value is deemed unreliable; see TRM for defini...
# 6 6 MATHERROR Mathematical error in computing value
# 7 7 FITFAILED Attempted fit for property failed
# 8 8 NEARBOUND Fitted value is too near an imposed boundary; ...
# 9 9 NOCORRECTION Appropriate correction not available
# 10 10 MULTICOMP Multi-component velocity features present
# 11 30 DONOTUSE Do not use this spaxel for science>
ha.pixmask.mask # == ha.mask
# array([[1073741843, 1073741843, 1073741843, ..., 1073741843, 1073741843,
# 1073741843],
# ...,
# [1073741843, 1073741843, 1073741843, ..., 1073741843, 1073741843,
# 1073741843]])
ha.pixmask.bits
# [[[0, 1, 4, 30],
# ...,
# [0, 1, 4, 30]]]
ha.pixmask.labels
# [[['NOCOV', 'LOWCOV', 'NOVALUE', 'DONOTUSE'],
# ...,
# ['NOCOV', 'LOWCOV', 'NOVALUE', 'DONOTUSE']]]
ha.pixmask.mask[17, 32] # 1073741843
ha.pixmask.bits[17][32] # [0, 1, 4, 30]
ha.pixmask.labels[17][32] # ['NOCOV', 'LOWCOV', 'NOVALUE', 'DONOTUSE']With MANGA_DAPPIXMASK, you might want to translate individual mask values, bits, or labels:
ha.pixmask.values_to_bits(1073741843) # [0, 1, 4, 30]
ha.pixmask.values_to_labels(1073741843) #['NOCOV', 'LOWCOV', 'NOVALUE', 'DONOTUSE']
# Translate one label
ha.pixmask.labels_to_value('NOCOV') # 1
ha.pixmask.labels_to_bits('NOCOV') # [0]
# Translate multiple labels
ha.pixmask.labels_to_value(['NOCOV', 'UNRELIABLE']) # 33
ha.pixmask.labels_to_bits(['NOCOV', 'UNRELIABLE']) # [0, 5]You might want to produce a mask (e.g., to produce a custom mask for plotting):
# Mask of regions with no IFU coverage
nocov = ha.pixmask.get_mask('NOCOV')
# Mask of regions with low Halpha flux and marked as DONOTUSE
low_ha = (ha.value < 1e-17) * ha.pixmask.labels_to_value('DONOTUSE')
# Combine masks using bitwise OR (`|`)
my_mask = nocov | low_ha
fig, ax = ha.plot(mask=my_mask)See the marvin-plotting-tutorial (e.g., marvin-plotting-custom-map-axes) for more about custom masks.
Class Inheritance Diagram
marvin.utils.general.maskbit.Maskbit
Classes
marvin.utils.general.maskbit.Maskbit
Functions
marvin.utils.general.maskbit.Maskbit.get_mask marvin.utils.general.maskbit.Maskbit.labels_to_bits marvin.utils.general.maskbit.Maskbit.labels_to_value marvin.utils.general.maskbit.Maskbit.values_to_labels marvin.utils.general.maskbit.Maskbit.values_to_bits