Changes between Version 6 and Version 7 of Dvo_tutorial
- Timestamp:
- May 7, 2009, 1:37:59 AM (17 years ago)
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Dvo_tutorial
v6 v7 73 73 {{{ 74 74 # for the flatcorr catdir 75 75 76 76 Set the region for plotting and plot a coordinate grid: 77 77 region 314.7428 37.1718 3 … … 79 79 #Set the region for catalog extraction: 80 80 skyregion 310 320 33 40 81 81 82 82 # for the 20090327 catdir 83 83 region 60 0 5 … … 89 89 90 90 Show which images are present in the current skyregion: 91 {{{ 91 92 images 92 93 }}} 93 94 Extracting average quantities into vectors (similar to those in sm, or arrays in IDL or C etc.) is done via `avextract`; from the currently defined region by giving the `-region` argument: 95 {{{ 94 96 avextract -region RA DEC g r i y 95 97 [... takes a while for big regions with lots of measurements ...] 96 98 }}} 97 99 NB: From looking at the source code, the syntax is supposed to be: 100 {{{ 98 101 -region # take ra,dec limits from currently defined plotting 'region' 99 102 -skyregion ramin ramax decmin decmax # use ra,dec limits as given 100 103 no -region or -skyregion command # use previously defined skyregion 101 104 }}} 102 105 However, with the `-region` setting, the output list does not actually seem to be affected by changing the `region`. I.e. better use the `skyregion` variant! 103 106 104 107 Also note that there is only ever '''one''' active skyregion, ie. `avextract -skyregion` changes the skyregion in the same way as the `skyregion` command. You can see the currently active one with the 108 {{{ 105 109 skyregion 110 }}} 106 111 command. 107 112 108 113 In addition to the quantities themselves, there is both an uncertainty and scatter; I think, usually the scatter is reported in the `:err` version of quantities; for RA and DEC, the error is in dRA, dDEC (see `avextract --help fields`: 114 {{{ 109 115 avextract -region RA dRA DEC dDEC g g:err r r:err i i:err y y:err 110 116 }}} 111 117 '''Note there have been problems with the calculations of some scatter/error columns, so not all of them may be there.''' 112 118 113 119 To see which vectors you've loaded, say 120 {{{ 114 121 vectors 115 122 }}} 116 123 There are two more `extract` commands: 117 124 * `mextract` extracts measurements; however, one can't compute colours from these (e.g.) because they are returned without any notion of which entry in the vector belongs to which object … … 123 130 124 131 The `avextract`, `mextract` and `mmextract` commands allow restricting the rows that are returned by adding a SQL-like `where` clause: 132 {{{ 125 133 avextract -region RA DEC g r i y where g-r < 0 126 134 }}} 127 135 === Find out which images contain a given ra, dec === 128 136 137 {{{ 129 138 gimages 314.7428 37.1718 -region 130 139 }}} 131 140 == Plotting and computing == 132 141 133 142 To plot two vectors against each other, say 143 {{{ 134 144 limits g r 135 145 box 136 146 plot g r 137 147 }}} 138 148 To compute and plot new vectors, say 139 149 150 {{{ 140 151 set gr = g - r 141 152 clear … … 143 154 box 144 155 plot gr r 145 156 }}} 146 157 To plot things in sky coordinates, use `cplot`: 158 {{{ 147 159 cplot RA DEC 148 160 }}} 149 161 = Things we want to know/do = 150 162 … … 164 176 If you have gpc1 as your default camera in your ~/.ptolemyrc, you can omit the -D CAMERA gpc1. 165 177 178 {{{ 166 179 The Relphot command comes from [wiki:IPPstripe82] 167 * Pull out star/galaxy separation flag, restrict sample to stars180 }}} * Pull out star/galaxy separation flag, restrict sample to stars 168 181 * Filter on magnitude errors 169 182 * Dump ra dec mag magerr stargalflag into ASCII file for customized analysis
