Here are some examples of tcopy
:
stilts tcat obs1.fits obs2.fits out=combined.fits
stilts tcat ifmt1=ascii in1=obs1.txt ifmt2=ascii in2=ob2.txt omode=stats
stilts tcat in1=survey.vot.gz ifmt2=csv in2=more_data.csv icmd1='addskycoords fk5 galactic RA2000 DEC2000 GLON GLAT' \ icmd1='keepcols "OBJ_ID GLON GLAT"' \ icmd2='keepcols "ident gal_long gal_lat"' \ omode=topcat
ifmt1
parameter is required since
VOTables can be detected automatically), and the other is a
comma-separated-values file (for which the ifmt2=csv
parameter must be given).
In the second place, the column structure of the two tables may be
quite different. By pre-processing the two tables using the
icmd1
& icmd2
parameters, we produce
in each case an input table which consists of three columns of
compatible types and meanings: an integer identifier and floating point
galactic longitude and latitude coordinates.
The second table contains such columns to start with,
but the first table requires an initial step to convert
FK5 J2000.0 coordinates to galactic ones.
tcat
joins the two doctored tables together, to produce
a table which contains only these three columns, with all the rows
from both input tables, and sends the result directly
to a new or running instance of TOPCAT.