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: http://xmm.vilspa.esa.es/sas/7.0.0/doc/selectlib/node19.html
Дата изменения: Wed Jun 28 22:42:53 2006
Дата индексирования: Sat Dec 22 11:44:57 2007
Кодировка:
Поисковые слова: п п п п п п п п п п п р п р п р п р п р п р п р п р п р п р п р п
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XMM-Newton Science Analysis System
selectlib (selectlib-4.68) [xmmsas_20060628_1801-7.0.0]
Meta Index / Home Page / Description / File-based filters
mask(x.msk,x0,y0,x,y)
is true if the value of the mask image shifted by
in the data set x.msk at the location
is not equal to zero.
If the specified mask image contains the
World-Coordinate-System (WCS) attributes
CRPIXx, CRVALx, CDELTx with
x being either 1 or 2, image coordinate values are computed
from the respective integer pixel numbers
as
![\begin{displaymath}
r_i(n) = (n - \index{Attributes!CRPIX}{\tt CRPIX}_i) \times...
... CDELT}_i + \index{Attributes!CRVAL}{\tt CRVAL}_i,\qquad i=1,2
\end{displaymath}](img53.png) |
(1) |
This effectively defines the pixel size in the mask image as
.
If symbolic names have been specified in the mask filter command
as x and y and the corresponding columns in the
processed table have associated WCS-attributes
TCRPXx, TCRVLx, and TCDLTx respectively
the actual coordinate values are calculated as above. This effectively
defines the table pixel size as
.
The mask filter expression then evaluates to true for each ``table pixel''
if it has no overlap with any image mask pixel.
Mask images are ordinary rectangular arrays of any
integral type supported by the dal.
XMM-Newton SOC/SSC -- 2006-06-28