DVO provides several ways to access the photometry information stored in the database. Several simple commands allow the user to extract 1 dimensional information directly from one of the primary database tables. The commands are:

• imextract
• avextract
• mextract
• imsearch
• detsearch

imextract

  dvo: imextract
  USAGE: imextract (value) [-region] [-time start range] [-photcode photcode]
  dvo: imextract help
  value may be one of the following:
   ra dec airmass Mcal dMcal Xm photcode time fwhm exptime nstar ncal sky flag

The extracted data is saved in a vector with the same name used to select the column. The vector name will have the same case as the choice given, but the column selection is case-insensitive (since there are no ambiguities in the database columns names by case).

avextract

  dvo: avextract
  USAGE: avextract (from) (value) [options]
    from: cpt name or 'all'
    value: average.parameter or photcode
  dvo: avextract all help
  value may be one of the following:
   ra dec dmag Nmeas Nmiss Xm Xp Nphot Ncode flag type

This command takes as the first argument the name of one of the database regions. Alternatively, all regions currently displayed may be selection with the word 'all'. The second option specifies which column to select from the Average table. In addition to the basic data columns (ra, dec, etc), the magnitude-related average values (mag, dmag, Xm, Nphot, Ncode) are coupled to a photcode, which is thus required for these selections. The value 'mag' may also be subsituted with a primary or secondary photcode. Eg:

  avextract all ra : select ra for all objects in displayed region
  avextract all g  : select g magnitudes
  avextract all mag -photcode r : select r magnitudes 
  avextract all Xm -photcode r  : select chisq values for r average mags

mextract

  dvo: mextract
  USAGE: mextract (from) (value) [options]
    from: cpt name or 'all'
    value: measure.parameter or photcode
  dvo: mextract all help
  value may be one of the following:
   ra dR dec dD mag dmag Mrel Mcal photcode time fwhm dophot xccd yccd xmosaic ymosaic flags

This command takes as the first argument the name of one of the database regions. Alternatively, all regions currently displayed may be selection with the word 'all'. The second option specifies which column to select from the Measure table. In addition to the basic data columns (ra, dec, etc), the magnitude-related average values (mag, dmag) are coupled to a photcode, which is thus required for these selections. The value 'mag' may also be subsituted with a primary or secondary photcode. Eg:

  mextract all ra : select ra for all objects in displayed region
  mextract all g  : select g magnitudes
  mextract all mag -photcode r : select r magnitudes 
  mextract all Xm -photcode r  : select chisq values for r average mags

option filtering

-time (start) (range)
select data for images within the given time range. The start date is given in the format YYYY/MM/DD,hh:mm:ss (any of these element may be dropped, in which case they default to 00 [for hh,mm,ss] or 01 [for MM,DD]). The date may also be written as a number of days followed by j (JD) or J (MJD). The two special date names "now" and "today" are also valid. The range is written as a number followed by a unit, with valid units of s (seconds), m (minutes), h (hours), d (days). Times are in UT. For example:

 -time 2001/1/1 30d : select the range starting at midnight on 2001/1/1
  and ending 30 days (86400*30 seconds) later.

 -time now -3h : select the time range starting three hours ago and
  ending now.