Source code for sunpy.instr.aia

# -*- coding: utf-8 -*-
"""
Provides processing routines for data captured with the AIA instrument on SDO.
"""
import numpy as np
import astropy.units as u

from sunpy.map.sources.sdo import AIAMap, HMIMap

__all__ = ['aiaprep']


[docs]def aiaprep(aiamap): """ Processes a level 1 `~sunpy.map.sources.sdo.AIAMap` into a level 1.5 `~sunpy.map.sources.sdo.AIAMap`. Rotates, scales and translates the image so that solar North is aligned with the y axis, each pixel is 0.6 arcsec across, and the center of the sun is at the center of the image. The actual transformation is done by Map's :meth:`~sunpy.map.mapbase.GenericMap.rotate` method. This function is similar in functionality to aia_prep() in SSWIDL, but it does not use the same transformation to rotate the image and it handles the meta data differently. It should therefore not be expected to produce the same results. Parameters ---------- aiamap : `~sunpy.map.sources.sdo.AIAMap` instance A `sunpy.map.Map` from AIA Returns ------- newmap : A level 1.5 copy of `~sunpy.map.sources.sdo.AIAMap` Notes ----- This routine makes use of Map's :meth:`~sunpy.map.mapbase.GenericMap.rotate` method, which modifies the header information to the standard PCi_j WCS formalism. The FITS header resulting in saving a file after this procedure will therefore differ from the original file. """ if not isinstance(aiamap, (AIAMap, HMIMap)): raise ValueError("Input must be an AIAMap or HMIMap.") # Target scale is 0.6 arcsec/pixel, but this needs to be adjusted if the map # has already been rescaled. if ((aiamap.scale[0] / 0.6).round() != 1.0 * u.arcsec / u.pix and aiamap.data.shape != (4096, 4096)): scale = (aiamap.scale[0] / 0.6).round() * 0.6 * u.arcsec else: scale = 0.6 * u.arcsec # pragma: no cover # can't test this because it needs a full res image scale_factor = aiamap.scale[0] / scale tempmap = aiamap.rotate(recenter=True, scale=scale_factor.value, missing=aiamap.min()) # extract center from padded aiamap.rotate output # crpix1 and crpix2 will be equal (recenter=True), as aiaprep does not work with submaps center = np.floor(tempmap.meta['crpix1']) range_side = (center + np.array([-1, 1]) * aiamap.data.shape[0] / 2) * u.pix newmap = tempmap.submap(u.Quantity([range_side[0], range_side[0]]), u.Quantity([range_side[1], range_side[1]])) newmap.meta['r_sun'] = newmap.meta['rsun_obs'] / newmap.meta['cdelt1'] newmap.meta['lvl_num'] = 1.5 newmap.meta['bitpix'] = -64 return newmap