Provided by: stilts_3.1.5-1_all bug

NAME

       stilts-tapskymatch - Crossmatches table on sky position against TAP table

SYNOPSIS

       stilts tapskymatch [ifmt=<in-format>] [istream=true|false] [in=<table>] [icmd=<cmds>]
                          [ocmd=<cmds>]
                          [omode=out|meta|stats|count|cgi|discard|topcat|samp|tosql|gui]
                          [out=<out-table>] [ofmt=<out-format>] [inlon=<expr/deg>]
                          [inlat=<expr/deg>] [tapurl=<url-value>] [taptable=<name>]
                          [taplon=<column>] [taplat=<column>] [tapcols=<colname,...>]
                          [sr=<expr/deg>] [find=all|best|each|each-dist] [blocksize=<int-value>]
                          [maxrec=<int-value>] [sync=true|false] [blockmaxrec=<nrow>]
                          [compress=true|false] [fixcols=none|dups|all] [suffixin=<label>]
                          [suffixremote=<label>]

DESCRIPTION

       tapskymatch allows you to perform a positional crossmatch of a local table with  one  held
       in a remote TAP service, as long as that TAP supports upload queries. This task does three
       main jobs. First, it prepares the ADQL queries and TAP negotiations for you  so  that  you
       don't  need  to  remember  the syntax for performing positional crossmatches against a TAP
       service. Second, it organises data transfer so that only those columns required (basically
       the  positional  ones)  are transmitted to and from the service, to save on bandwidth. And
       third it divides the job up into chunks, so that the TAP service only  has  to  perform  a
       manageable-sized  query  at  a  time.  If  the job is large this chunking can be useful to
       monitor progress of the job, and it also  allows  you  to  perform  a  match  which  would
       otherwise hit the upload or output limits imposed by the service.

       The  positional  match may be done in any spherical coordinate system, it's up to the user
       to ensure that the same coordinates are provided for the local and remote tables.

       Note that cdsskymatch provides similar functionality by  accessing  a  different  external
       service,  which  is  usually  much  faster;  if the table you wish to match is part of the
       VizieR database, you may wish to use that command instead.

OPTIONS

       ifmt=<in-format>
              Specifies the format of the input table as specified by  parameter  in.  The  known
              formats  are  listed in SUN/256. This flag can be used if you know what format your
              table is in. If it has the special value (auto) (the default), then an attempt will
              be made to detect the format of the table automatically. This cannot always be done
              correctly however, in which case the program will exit  with  an  error  explaining
              which formats were attempted.

       istream=true|false
              If  set  true,  the  input  table  specified  by the in parameter will be read as a
              stream. It is necessary to give the ifmt parameter in this case. Depending  on  the
              required operations and processing mode, this may cause the read to fail (sometimes
              it is necessary to read the table more than once). It is not normally necessary  to
              set this flag; in most cases the data will be streamed automatically if that is the
              best thing to do. However it can sometimes  result  in  less  resource  usage  when
              processing large files in certain formats (such as VOTable).

       in=<table>
              The location of the input table. This may take one of the following forms:

                * A filename.

                * A URL.

                * The  special  value  "-", meaning standard input. In this case the input format
                  must be given explicitly using the ifmt parameter. Note that  not  all  formats
                  can be streamed in this way.

                * A  system  command  line  with  either  a  "<" character at the start, or a "|"
                  character at the end ("<syscmd" or "syscmd|"). This executes the given pipeline
                  and  reads  from its standard output. This will probably only work on unix-like
                  systems.
               In any case, compressed data in one of the supported  compression  formats  (gzip,
              Unix compress or bzip2) will be decompressed transparently.

       icmd=<cmds>
              Specifies  processing  to be performed on the input table as specified by parameter
              in, before any other processing has taken place. The value of this parameter is one
              or  more  of  the  filter commands described in SUN/256. If more than one is given,
              they must be separated  by  semicolon  characters  (";").  This  parameter  can  be
              repeated  multiple  times on the same command line to build up a list of processing
              steps. The sequence of commands given in this way defines the  processing  pipeline
              which is performed on the table.

              Commands may alteratively be supplied in an external file, by using the indirection
              character '@'. Thus a value of "@filename" causes the file filename to be read  for
              a  list of filter commands to execute. The commands in the file may be separated by
              newline characters and/or semicolons, and lines which are blank or which start with
              a '#' character are ignored.

       ocmd=<cmds>
              Specifies  processing  to  be  performed  on  the  output  table,  after  all other
              processing has taken place. The value of this parameter  is  one  or  more  of  the
              filter  commands  described  in  SUN/256.  If  more than one is given, they must be
              separated by semicolon characters (";"). This parameter can  be  repeated  multiple
              times on the same command line to build up a list of processing steps. The sequence
              of commands given in this way defines the processing pipeline which is performed on
              the table.

              Commands may alteratively be supplied in an external file, by using the indirection
              character '@'. Thus a value of "@filename" causes the file filename to be read  for
              a  list of filter commands to execute. The commands in the file may be separated by
              newline characters and/or semicolons, and lines which are blank or which start with
              a '#' character are ignored.

       omode=out|meta|stats|count|cgi|discard|topcat|samp|tosql|gui
              The  mode  in which the result table will be output. The default mode is out, which
              means that the result will be written as a new  table  to  disk  or  elsewhere,  as
              determined  by the out and ofmt parameters. However, there are other possibilities,
              which correspond to uses to which a table can be put other than outputting it, such
              as  displaying  metadata,  calculating  statistics, or populating a table in an SQL
              database. For some values of this parameter,  additional  parameters  (<mode-args>)
              are required to determine the exact behaviour.

              Possible values are

                * out

                * meta

                * stats

                * count

                * cgi

                * discard

                * topcat

                * samp

                * tosql

                * gui
               Use the help=omode flag or see SUN/256 for more information.

       out=<out-table>
              The  location of the output table. This is usually a filename to write to. If it is
              equal to the special value "-" (the default) the output table will  be  written  to
              standard output.

              This parameter must only be given if omode has its default value of "out".

       ofmt=<out-format>
              Specifies  the format in which the output table will be written (one of the ones in
              SUN/256 - matching is case-insensitive and you can use just the first few letters).
              If  it  has the special value "(auto)" (the default), then the output filename will
              be examined to try to guess what sort of file is required usually by looking at the
              extension. If it's not obvious from the filename what output format is intended, an
              error will result.

              This parameter must only be given if omode has its default value of "out".

       inlon=<expr/deg>
              Longitude in degrees for the position of each row in  the  input  table.  This  may
              simply  be  a  column  name,  or  it may be an algebraic expression as explained in
              SUN/256. The coordinate system must match that used  for  the  coordinates  in  the
              remote table.

       inlat=<expr/deg>
              Longitude  in  degrees  for  the  position of each row in the input table. This may
              simply be a column name, or it may be  an  algebraic  expression  as  explained  in
              SUN/256.  The  coordinate  system  must  match that used for the coordinates in the
              remote table.

       tapurl=<url-value>
              The base URL of a Table Access Protocol service. This is the  bare  URL  without  a
              trailing "/[a]sync".

              The  default  values  of  the  various  endpoints (sync and async query submission,
              tables metadata, service-provided examples etc) use this URL as a parent and append
              standard sub-paths. However, other parameters (syncurl, asyncurl, ...) are provided
              so that the different endpoints can be set individually if required.

       taptable=<name>
              Name of the table in the given TAP service  against  which  the  matching  will  be
              performed.

       taplon=<column>
              Longitude  in  degrees for the position of each row in the remote table. This is an
              ADQL expression interpreted within the TAP service, typically just a  column  name.
              The coordinate system must match that used for the input table.

       taplat=<column>
              Latitude  in  degrees  for the position of each row in the remote table. This is an
              ADQL expression interpreted within the TAP service, typically just a  column  name.
              The coordinate system must match that used for the input table.

       tapcols=<colname,...>
              Comma-separated list of column names to retrieve from the remote table. If no value
              is supplied (the default), all columns from the remote table will be returned.

       sr=<expr/deg>
              Maximum distance in degrees from  the  local  table  (lat,lon)  position  at  which
              counterparts  from  the remote table will be identified. This is an ADQL expression
              interpreted within the TAP service, so it may be a constant value  or  may  involve
              columns in the remote table.

       find=all|best|each|each-dist
              Determines which pair matches are included in the result.

                * all: All matches

                * best: Matched rows, best remote row for each input row

                * each: One row per input row, contains best remote match or blank

                * each-dist: One row per input row, column giving distance only for best match
               Note only the all mode is symmetric between the two tables.

       blocksize=<int-value>
              The  number of rows uploaded in each TAP query. TAP services may have limits on the
              number of rows in a table uploaded for matching. This command can  therefore  break
              up input tables into blocks and make a number of individual TAP queries to generate
              the result. This parameter controls the maximum number of  rows  uploaded  in  each
              individual  request.  For an input table with fewer rows than this value, the whole
              thing is done as a single query.

       maxrec=<int-value>
              Limit to the number of rows resulting from this operation. If the value is negative
              (the default) no limit is imposed. Note however that there can be truncation of the
              result if the number of records returned from a single chunk exceeds limits imposed
              by the service.

       sync=true|false
              Determines  whether  the  TAP  queries are submitted in synchronous or asynchronous
              mode. Since this command uses chunking to  keep  requests  to  a  reasonable  size,
              hopefully  requests  will  not  take  too long to execute, therefore the default is
              synchronous (true).

       blockmaxrec=<nrow>
              Sets the MAXREC parameter passed to the TAP service for each uploaded  block.  This
              allows  you  to request that the service overrides its default limit for the number
              of rows output from a single query. The service may still impose some "hard"  limit
              beyond which the output row count cannot be increased.

              Note  this  differs from the maxrec parameter, which gives the maximum total number
              of rows to be returned from this command.

       compress=true|false
              If true, the service  is  requested  to  provide  HTTP-level  compression  for  the
              response  stream (Accept-Encoding header is set to "gzip", see RFC 2616). This does
              not guarantee that compression will happen but if the service honours this  request
              it  may  result  in  a  smaller  amount  of  network traffic at the expense of more
              processing on the server and client.

       fixcols=none|dups|all
              Determines how input columns are renamed  before  use  in  the  output  table.  The
              choices are:

                * none: columns are not renamed

                * dups:  columns which would otherwise have duplicate names in the output will be
                  renamed to indicate which table they came from

                * all: all columns will be renamed to indicate which table they came from
               If columns are renamed, the new ones are determined by suffix* parameters.

       suffixin=<label>
              If the fixcols parameter is set so that input columns  are  renamed  for  insertion
              into the output table, this parameter determines how the renaming is done. It gives
              a suffix which is appended to all renamed columns from the input table.

       suffixremote=<label>
              If the fixcols parameter is set so that input columns  are  renamed  for  insertion
              into the output table, this parameter determines how the renaming is done. It gives
              a suffix which is appended to all renamed columns from the TAP result table.

SEE ALSO

       stilts(1)

       If the package stilts-doc is installed, the full documentation  SUN/256  is  available  in
       HTML format:
       file:///usr/share/doc/stilts-doc/sun256/index.html

VERSION

       STILTS version 3.1-5-debian

       This  is  the  Debian  version  of Stilts, which lack the support of some file formats and
       network protocols. For differences see
       file:///usr/share/doc/stilts/README.Debian

AUTHOR

       Mark Taylor (Bristol University)

                                             Mar 2017                       STILTS-TAPSKYMATCH(1)