Loading table into TOPCAT from files or URLs is done either
using the Load Table dialogue
or one of its sub-windows,
or from the command line when you start the program.
For some file formats (e.g. FITS, VOTable, CDF),
the format can be automatically determined by
looking at the file content, regardless of filename;
for others (e.g. CSV files with a ".csv" extension),
TOPCAT may be able to use the filename as a hint to guess the format
(the details of these rules are given in the format-specific
subsections below).
In other cases though,
you will have to specify the format that the file is in.
In the Load Window, there is a selection box from which you can
choose the format, and from the command line you use the
-f flag - see Section 10 for details.
You can always specify the format rather than using automatic detection
if you prefer - this is slightly more efficient,
and may give you a more detailed error message
if a table fails to load.
In either case, table locations may be given as filenames or as URLs, and any data compression (gzip, unix compress and bzip2) will be automatically detected and dealt with - see Section 4.2.
Some of the formats
(e.g. FITS, VOTable)
are capable of storing more than one table;
usually loading such files loads all the tables into TOPCAT.
If you want to specify only a single table,
you can give a position indicator either after a "#" sign
at the end of the filename or using the
Position in file field in the
Filestore Browser or similar.
The details of the syntax for this is given in the relevant
format description below.
The following sections describe the table formats which TOPCAT can read.