IPP Software Navigation Tools IPP Links Communication Pan-STARRS Links

Ignore:
Timestamp:
Sep 27, 2005, 7:43:49 AM (21 years ago)
Author:
eugene
Message:

minor cleanups, web edits

File:
1 edited

Legend:

Unmodified
Added
Removed

  • trunk/Ohana/doc/www/html/DVO/relphot.htm

    r4726 r5144  
     1
     2<h2> relphot outline </h2>
     3
     4<ul>
     5<li> load data
     6     <ul>
     7     <li> images: match photcode and time range, reset flags
     8     <li> measure: select subset matching restritions on:
     9          photcode, time, dM, Minst, Mag, dophot == 1
     10     </ul>
     11<li> iterate to find Mcal, image.flags:
     12<li> write out modified Mcal values to image table
     13<li> write out modified Mcal values to measure table
     14<li> write out modified Mrel values to average table
     15</ul>
     16
     17<h2> relphot overview </h2>
     18
     19<p> relphot has two primary purposes:<br>
     20<ul>
     21<li> calculate <b>Mcal</b> for images / measures
     22<li> calculate <b>Mrel</b> for stars
     23</ul>
     24
     25<p> relphot can also be used to determine the mosaic grid used to generate
     26photometrically corrected flats (-grid option).
     27
     28<h2> data exclusion </h2>
     29
     30<p> relphot uses only a subset of the photometry data to calculate
     31Mcal and Mrel.  In the first stage, calculation of the Mcal values,
     32relphot loads the photometry data from each relevant catalog and
     33creates an internal subset catalog with the function
     34<em>bcatalog</em>, excluding some of the irrelevant data.  In
     35addition, it uses flags to mark some of the data as invalid for the
     36processing.
     37
     38<b> bcatalog exclusions </b>
     39<ul>
     40<li> measure.photcode not equivalent to requested photcode
     41<li> measure.dophot != 1
     42<li> measure.Mcat > MAG_LIM
     43<li> measure.dM > SIGMA_LIM
     44<li> measure.Minst out of range (ImagMin - ImagMax) [optional]
     45<li> measure.t out of range (TSTART, TSTOP)
     46</ul>
     47
     48<b> flagged data </b>
     49
     50<b> flagged image data </b>
     51
     52images can be flagged by setting bits of <b>image.code</b>
     53
     54stars can be flagged by setting bits of <b>average.code</b>
     55
     56measures can be flagged by setting bits of <b>measure.flag</b>
     57
     58<b>image.code</b>
     59
     60ID_IMAGE_NOCAL : ignore, irrelevant
     61ID_IMAGE_POOR  : image measured bad
     62ID_IMAGE_SKIP  : externally known bad
     63
     64dMcal > VALUE       FLAG_IMAGE_SCATTER <em>clean_images</em>
     65fabs(Mcal) > VALUE  FLAG_IMAGE_ZEROPT  <em>clean_images</em>
     66
     67dMcal > VALUE       FLAG_IMAGE_SCATTER <em>clean_mosaics</em>
     68fabs(Mcal) > VALUE  FLAG_IMAGE_ZEROPT  <em>clean_mosaics</em>
     69
     70<em> mark_images </em> does not seem to do anything useful?
     71
     72<b>average.code</b>
     73
     74Ngood < MEAS_TOOFEW                     <em>setMrel</em>
     75Ngood < MEAS_TOOFEW                     <em>clean_measures</em>
     76ChiSq > STAR_CHISQ                      <em>clean_stars</em>
     77dM    > STAR_SCATTER                    <em>clean_stars</em>
     78
     79average.code (STAR_BAD) is not saved by relphot: it is set by
     80clean_stars, clean_measures, and setMrel, but not setMrelOutput.
     81STAR_BAD should only be internal since it depends on the photcode, but
     82is not associated with a specific photcode in the data.  Just in case,
     83it is reset to 0 in setMrelFinal.
     84
     85<b>measure.flag</b>
     86
     87X,Y out of range                        <em>setExclusions</em>
     883 sigma clipping                        <em>clean_measures</em>
     89
     90<h2> setting Mrel final value </h2>
     91
     92setMrelFinal is used to set the final average.Mrel values.  We do this
     93in 4 stages.  In each stage, we set the Mrel values for stars which
     94have not already been set, based on the current exclusion settings.
     95At successive stages, we relax the exclusions, allowing the more
     96spurious objects to have a valid Mrel value to be set.  In this loop,
     97we actually run setMrelOutput twice: once to get the approximate Mrel
     98value, then we flag the outlier measurements with clean_measure,
     99then we redetermine the Mrel values on this basis, and mark the stars
     100for exclusion from the next iteration. 
     101
     102<pre>
     103exclude on
     104 photcode       0 1 2 3
     105 time range     0 1 2 3
     106 MEAS_POOR      0 1 2 3
     107 MEAS_TOOFEW    0 1 2 3
     108 dophot == 10   0 1 2
     109 inst mag       0 1 2
     110 dophot != 1,2  0 1 
     111 ID_IMAGE_POOR  0 1
     112 ID_IMAGE_SKIP  0 1
     113 dophot != 1    0
     114 measure.dM     0
     115</pre>
     116
     117for all relphot runs, Mrel is re-calculated, and measures are marked
     118at least if they are outliers in mag or ccd area.
     119
     120setMrel.output needs to do a few things differently from setMrel:
     121<ul>
     122<li> set measure.Mcal (skipped in setMrel.basic)
     123<li> set average.Mrel if N < TOO_FEW (not STAR_BAD) (optional!)
     124<li> use MAX (stats.error, stats.sigma) (optionally)
     125<li> allow STAR_BAD?
     126</ul>
     127
     128<h2> imphotset </h2>
     129
     130imphotset allows you to set certain phot.image table entries.  here
     131are the options:
     132
     133imphotset [-photcode code] [-name foo] [-trange (start) (stop)] -flag and value
     134
     135
     136Here is a complete list of relphot configuration variable names, a
     137quick description, and reasonable values to start with:
     138
     139<pre>
     140--- configuration variables used by relphot ---
     141MAG_LIM : float
     142  ignore measurements fainter than this absolute magnitude
     143
     144SIGMA_LIM : float
     145  ignore measurements with magnitude error larger than this value
     146
     147STAR_SCATTER : float
     148  mark stars as bad if their scatter is larger than this value
     149
     150IMAGE_SCATTER : float
     151  mark images as bad if their scatter is larger than this value
     152
     153IMAGE_OFFSET : float
     154  mark images as bad if the absolute value of thie zero point offset
     155  is larger than this number
     156
     157STAR_CHISQ : float
     158  mark stars as variable if their reduced chisq are larger than this value
     159
     160STAR_TOOFEW : int
     161  mark stars as bad if the have fewer than this number of valid measurements
     162
     163IMAGE_TOOFEW : int
     164  mark images as bad if the have fewer than this number of valid measurements
     165
     166IMAGE_GOOD_FRACTION : float
     167  mark images as bad if the have fewer than this fraction of valid measurements 
     168
     169IMAGE_CATALOG : string
     170  name of the image catalog file
     171
     172IMAGE_CATALOG_TEMPLATE : string
     173  name of the template file to create the image catalog file
     174
     175CATALOG_TEMPLATE : string
     176  name of the template file to create the catalog file
     177
     178GSCFILE : string
     179  name of the GSC region table
     180
     181CATDIR : string
     182  directory where the database is stored
     183
     184PHOTCODE_FILE : string
     185  file containing photometry code information
     186
     187ZERO_PT : float
     188  default zero point for random data
     189
     190RELPHOT_GRID_X : int
     191  scale of mosaic correction grid
     192
     193RELPHOT_GRID_Y : int
     194  scale of mosaic correction grid
     195
     196RELPHOT_GRID_BINNING : int
     197  deprecated
     198
     199CAMERA_CONFIG : string
     200  name of the file containing descriptive information about the camera
     201
     202--- sample ConfigFile entries with typical values ---
     203
     204MAG_LIM                  24.0
     205SIGMA_LIM                 0.05
     206STAR_SCATTER              0.05
     207IMAGE_SCATTER             0.05
     208IMAGE_OFFSET              0.2
     209STAR_CHISQ               10.0
     210STAR_TOOFEW               3
     211IMAGE_TOOFEW             10
     212IMAGE_GOOD_FRACTION     
     213IMAGE_CATALOG            $CATDIR/Images.dat
     214IMAGE_CATALOG_TEMPLATE   $REFSDIR/elixir/template.cat
     215CATALOG_TEMPLATE         $REFSDIR/elixir/template.cat
     216GSCFILE                  $REFSDIR/gsc/GSCregions.tbl
     217CATDIR                   $CATDIR
     218PHOTCODE_FILE            $CONFDIR/camera/$CAMERA.photcode
     219ZERO_PT                  25.0
     220RELPHOT_GRID_X           4
     221RELPHOT_GRID_Y           8
     222RELPHOT_GRID_BINNING     512
     223CAMERA_CONFIG            $CONFDIR/camera/$CAMERA.config
     224</pre>
Note: See TracChangeset for help on using the changeset viewer.