The RD_xxx routines (RD_BDA, RD_HDA, RD_SDA, RD_WDA, RD_XDA)
allow you to read the reformatted data files. Each
routine has the same calling sequence, and there is a generic reading routine
called RD_XDA which will read data for any of the instruments. After you have
established the input file name(s) (infil) and which data sets to
extract (dset_arr), you can read the data by a command:
IDL> rd_sda, infil, dset_arr, index, data
IDL> rd_sda, infil, dset_arr, index, data, roadmap
IDL> rd_xda, infil, -1, index, /nodata
index is a structure which describes the data. There is one index structure
for each dataset. The roadmap is for all datasets in the files (not just
the selected datasets). It is possible to read all datasets in the file
by specifying -1 for dset_arr. The /nodata switch tells the routine
to only read the index and roadmap, not the data.