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### B.25.2 Examples

Here are some examples of `tapskymatch`:

    stilts tapskymatch tapurl=http://dc.g-vo.org/tap
                       taptable=twomass.data taplon=raj2000 taplat=dej2000
                       in=dr5qso.fits inlon=RA inlat=DEC sr=0.00027 find=all
                       out=qso_2mass.fits

  Matches a local catalogue `dr5qso.fits` against the table named `twomass.data` in the GAVO TAP service. The search radius is 1/3600 degrees (1 arcsecond) and all 2MASS sources within the radius of each input source are returned.

  If you run the command with "`stilts -verbose ...`" the text of the ADQL query submitted to the TAP service will (amongst other things) be logged on the console, and you will also see the number of rows uploaded and matched in each chunk.

    stilts tapskymatch tapurl=http://dc.g-vo.org/tap
                       taptable=rave.dr3 taplon=raj2000 taplat=dej2000
                       tapcols=name,raj2000,dej2000,pmra,pmde
                       in=hip_main.fits inlon=RAdeg inlat=DEdeg
                       icmd='keepcols "HIP RAdeg DEdeg pmra pmde"'
                       sr=0.00027
                       icmd='select nearMoc(\"III/265/ravedr3\",RAdeg,DEdeg,.00027)'
                       icmd=cache icmd=progress
                       blocksize=5000
                       fixcols=all suffixin=_hip suffixremote=_rave
                       find=best
                       omode=topcat

  This matches a local copy of the Hipparcos survey against a remote copy of the RAVE survey with a 1-arcsecond radius. The output table contains only the identifier, position and proper motion columns from both the input table (by using the `keepcols` filter) and the remote table (by specifying `tapcols`); the other columns are discarded. The `fixcols` and `suffix`* parameters ensure that a suffix is added to all the output column names, `_hip` for the input (Hipparcos) columns and `_rave` for the remote (RAVE) ones.

  Before uploading, the input table is preprocessed by selecting only those rows that fall within the actual footprint of the RAVE survey, by filtering with a MOC giving RAVE coverage (the RAVE dr3 MOC is also available at this URL). This step reduces the amount of data that needs to be uploaded, since only those rows in the given coverage region stand a chance of having a match in the remote table. Note use of the `nearMoc` function with the value of the match radius as the fourth parameter; this includes those objects which may be outside the actual MOC region but close enough that a match could still result.

  The `blocksize` parameter determines the number of rows uploaded at a time. If you receive warnings that the output has been truncated, you should decrease this number.

  Progress is displayed as the match continues. The `cache` filter must be applied upstream of (before) the `progress` filter itself for this to work, since otherwise the match processing reads all the input rows before the actual work is done, and the progress monitor completes before the match actually starts.

Next Previous Up Contents
Next: tcat: Concatenates multiple similar tables
Up: tapskymatch: Crossmatches table on sky position against TAP table
Previous: Usage

STILTS - Starlink Tables Infrastructure Library Tool Set
Starlink User Note256
STILTS web page: http://www.starlink.ac.uk/stilts/
Author email: m.b.taylor@bristol.ac.uk
Mailing list: topcat-user@jiscmail.ac.uk