To insert a catalogue in the Personal Data Base means to write, in the PDB
system files, the description of the catalogue characteristics,
then the PDB will have
a pointer to the user catalogue file, and DIRA2 will work on it.
The insertion of a catalogue in the PDB structure is carried out
in the following steps.
- Writing a file with the catalogue data in a compatible format; the
previous chapter has defined the characteristics of a valid DIRA2
data file. Typically the problems that the user meets in this phase are:
- Transform the coordinates values in a valid, format and normalize
proper motions to arcsec/years (see section );
The user can get the source CONVERT.FOR in [DIRA2.DEMO] that is a
template for coordinates conversion.
- Sometime is required to remove spurious records like titles or labels
- When a numerical field do not contains data it can be filled with space
characters. All the tasks of the package consider a black string in a
numerical field as 'lack of data' and don't use the record when that
field is required. Please do not use special values
(for example 9999.99)
or characters to define lack of data.
- When the original catalogue has many records for a single objects it
is required to rewrite this with a single record for object.
- It is better that the fields are separated by a column of blank;
in this case the user can run the DB_INSTAB to insert automatically
the catalogue in PDB.
- When the catalogue handles sky coordinates it is suggested to sort the
data on longitude coordinate (i.e. RA).
- On a VAX/VMS system to create fixed length records file is suggested.
The command DB_FIXA performs this job.
- Insertion of the information relative to the catalogue in the system
- The insertion can be executed manually by PDB_MANAG command and require
to know the characteristics of the catalogue files and fields. The
user must look into data file to get information or must have
a detailed catalogue documentation.
- First the user must decide the names of the fields of the new catalogue,
using the DB_INFO command he can get the acronimous already
defined in the vocabulary for the common physical quantities.
- The DB_INSTAB command inserts a catalogue in a PDB with minimal
effort. The file must contain the data fields separated by one or
of blank characters, or the task is not able to recognize the fields.
The fields of the
new catalogue are called V1, V2, ...Vn and the user have to use the
PDB_MANAG, after the automatic insertion, to change the names of
the catalogue's fields and to assign a code type to the fields that
contain coordinates, if they exist.
- When you define a new field you assign a name at a group of columns
(from charater X to character Y ) of the catalogue.
Then, in a catalogue file can exists columns that
are not linked with a field name, or (rare) columns that concerns to
- After the insertion of a new catalogue in the PDB the user can check
the data by means of the DB_CHECK task. The user must
verify the definition of the right sort key and code type for the
- Writing a documentation file that contains both the full
description of the catalogue, and the description of the codes used for the
fields. Obviously the documentation file is not strictly necessary for the
operation of routines, but it is strongly recommended.
When the catalogue to be inserted in the PDB is a sub-set extracted from a
system catalogue by means of DIRA2 commands, the operation 1) and 2) are
performed automatically. The name of the documentation file is that of the
To insert a catalogue written on tape or disk as a FITS table the user can
use the DB_FROMFT command. This works in an automatic way, reads the input
file, executes the conversion of the coordinate formats (when required) and
creates an ascii catalogue. Moreover updates the PDB system files with the
catalogue items. After the use of this command,
the catalogue is ready for its use in DIRA2.
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