Creating IDL maps from EIS data#
IDL maps are a widely used means of storing and using solar image data, and are very useful for comparing data-sets from different instruments. The sections below describe different ways of creating maps from EIS data. Please check Dominic Zarro's IDL map webpageContent unavailable! (broken link)https://solarb.mssl.ucl.ac.uk/JSPWiki/images/out.png for more details on how to use maps. A basic operation is to plot a map:
IDL> plot_map, map
Note that velocity and line width maps can be created from EIS data in addition to intensity maps.
Quick method#
An intensity map can be quickly generated from the EIS data object (DATA) using, e.g.,
IDL> mmap=data->mk_eis_map(195.12)
which simply sums all wavelength pixels in the data window containing the wavelength 195.12 line. This map should not be used for detailed science analysis, but is useful for taking a quick look at the data. Warning: if there is more than one emission line in the data window, then the map may not look as expected.
Creating a map using moments#
Moments are usually used as a quick means of estimating the intensity, velocity and width of an emission line without having to do Gaussian fits. They are obtained by doing, e.g.,
IDL> m=obj_new(‘eis_moment’,data,iwin=195.12)
A widget will pop up allowing you to define the emission line and continuum to be used for the moments.
A list of methods for 'm' can be obtained by doing:
IDL> m->help
With the moment object created, maps containing intensity, velocity and line width are created using:
IDL> intmap=m->mk_eis_map(195.12) IDL> velmap=m->mk_eis_map(195.12,/vel) IDL> widmap=m->mk_eis_map(195.12,/wid)
Creating a map from Gaussian fits#
These are done in the same way as the moments by adding the keyword /gauss:
IDL> m=obj_new(‘eis_moment’,data,iwin=195.12,/gauss)
You will again be asked to define the line and continuum for the fit.
The maps are created with:
IDL> intmap=m->mk_eis_map(195.12) IDL> velmap=m->mk_eis_map(195.12,/vel) IDL> widmap=m->mk_eis_map(195.12,/wid)