data:data_analysis_manual
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data:data_analysis_manual [2024/11/11 20:28] Peter Young [Line fitting] |
data:data_analysis_manual [2025/01/09 11:25] (current) eric buchlin Moved Python line fitting |
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| ==== Line fitting ==== | ==== Line fitting ==== | ||
| + | For IDL Gaussian fitting software, please check: **[[data:line_fitting_idl|IDL software for emission line fitting]]**. | ||
| - | === Fitting a Gaussian at each spatial pixel in a raster (IDL) === | + | Fitting in Python can be done with any fitting library, including [[https://docs.astropy.org/en/stable/modeling/|astropy.modelling]]. From astropy 7.0, there is a user-friendly way of doing the fitting in parallel ([[https://github.com/aperiosoftware/parallel-modeling-examples/blob/main/spice/Final_Tutorial.ipynb|tutorial]] by Stuart Mumford). |
| - | Spectra at each spatial pixel in a raster can be fit with Gaussians using the eis\_auto\_fit IDL routine developed for the Hinode/EIS mission (you must have the EIS branch in your Solarsoft distribution). The key step is to format a SPICE wavelength window into a "windata" structure using the routine spice\_getwindata. An example call is: | ||
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| - | '' | ||
| - | IDL> wd=spice\_getwindata(file) ; choose a wavelength window \\ | ||
| - | IDL> eis\_fit\_template,wd,template ; create a template for the fit\\ | ||
| - | IDL> eis\_auto\_fit,wd,fit,template=template\\ | ||
| - | IDL> eis\_fit\_viewer,wd,fit | ||
| - | '' | ||
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| - | The routine eis\_fit\_viewer is a GUI-based routine for browsing the fit results. More details on the eis\_auto\_fit suite of routines are available in [[https://doi.org/10.5281/zenodo.6339584 | ||
| - | |EIS Software Note 15]]. | ||
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| - | The EIS software enable a number of operations to be performed on windata structures, as described in [[https://sohoftp.nascom.nasa.gov/solarsoft/hinode/eis/doc/eis_notes/21_WINDATA/eis_swnote_21.pdf|EIS Software Note 21]]. For example, eis\_bin\_windata allows spatial binning of the rasters. | ||
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| - | If you have problems running the EIS software on SPICE data, please contact [[https://science.gsfc.nasa.gov/sed/bio/peter.r.young|Dr. Peter Young]]. | ||
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| - | === Fitting a Gaussian to a spatially-averaged spectrum (IDL) === | ||
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| - | In this scenario, a spatial region is selected in the raster, perhaps a bright point or a loop, and the spectra are averaged over this region to produce a single, 1D spectrum. Gaussians are then fit to this spectrum. The procedure is as follows: | ||
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| - | '' | ||
| - | IDL> map=spice\_make\_image(file,770.4) ; for Ne VIII 770.4\\ | ||
| - | IDL> mask=pixel\_mask\_gui(map) ; GUI routine for selecting pixel mask\\ | ||
| - | IDL> spec=spice\_mask\_spectrum(file,mask) ; create averaged spectrum\\ | ||
| - | IDL> spec\_gauss\_spice, spec ; GUI routine for fitting Gaussians | ||
| - | '' | ||
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| - | These routines are modified from routines originally written for Hinode/EIS. Further details can be found in [[https://doi.org/10.5281/zenodo.6339584 | ||
| - | |EIS Software Note 15]]. | ||
data/data_analysis_manual.1731353283.txt.gz · Last modified: 2024/11/11 20:28 by Peter Young
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