Документ взят из кэша поисковой машины. Адрес оригинального документа : http://xmm.vilspa.esa.es/sas/7.0.0/doc/selectlib/node15.html
Дата изменения: Wed Jun 28 22:42:53 2006
Дата индексирования: Sat Dec 22 11:47:55 2007
Кодировка:
Поисковые слова: http www.astronomy.ru forum index.php topic 4644.0.html

XMM-Newton Science Analysis System


selectlib (selectlib-4.68) [xmmsas_20060628_1801-7.0.0]

Meta Index / Home Page / Description

Special region filter functions

The following functions evaluate to true if a given point lies inside or on the border of the specified geometric figure:

• point(x0,y0,Xcolumn,Ycolumn)
• line(x0,y0,x1,y1,Xcolumn,Ycolumn)
• circle(xCenter,yCenter,radius,Xcolumn,Ycolumn)
• sector(xCenter,yCenter,fromAngle,toAngle,Xcolumn,Ycolumn) or
  pie(xCenter,yCenter,fromAngle,toAngle,Xcolumn,Ycolumn)
• ring(xCenter,yCenter,radius1,radius2,Xcolumn,Ycolumn) or
  annulus(xCenter,yCenter,radius1,radius2,Xcolumn,Ycolumn)
• ellipse(xCenter,yCenter,xHalfWidth,yHalfWidth,rotation,Xcolumn,Ycolumn)
• elliptannulus(xCenter,yCenter,xHalfWidthInner,yHalfWidthInner
  xHalfWidthOuter,yHalfWidthOuter,rotationInner,rotationOuter,Xcolumn,Ycolumn) or
  elliptring(xCenter,yCenter,xHalfWidthInner,yHalfWidthInner
  xHalfWidthOuter,yHalfWidthOuter,rotationInner,rotationOuter,Xcolumn,Ycolumn)
• box(xCenter,yCenter,xHalfWidth,yHalfWidth,rotation,Xcolumn,Ycolumn)
• rectangle(xLoLeft,yLoLeft,xUpRight,yUpRight,rotation,Xcolumn,Ycolumn)
• rhombus(xCenter,yCenter,xHalfWidth,yHalfWidth,rotation,Xcolumn,Ycolumn) or
  diamond(xCenter,yCenter,xHalfWidth,yHalfWidth,rotation,Xcolumn,Ycolumn)
• polygon(x1,y1,x2,y2,x3,y3,x4,y4,...,Xcolumn,Ycolumn)
• polygon2(x1,y1,x2,y2,x3,y3,x4,y4,...,Xcolumn,Ycolumn)

where

$\parbox{.30\textwidth}{{\tt (x0,y0)}}$ 		 : $\parbox{.7\textwidth}{a coordinate pair defining a point - thetwo po...
...yColumn)} (see below) mustcoincide for the {\tt point} function to return true}$

$\parbox{.30\textwidth}{{\tt (x0,y0,x1,y1)}}$ 		 : $\parbox{.7\textwidth}{two points defining a line - the testpoint {\t...
... lie on the line to within 0.5units for the {\tt line} function to return true}$

$\parbox{.30\textwidth}{{\tt (x1,y1,x2,y2,...)}}$ 		 : $\parbox{.7\textwidth}{the corner points of apolygon}$

$\parbox{.30\textwidth}{{\tt (xCenter,yCenter)}}$ 		 : $\parbox{.7\textwidth}{the (x,y) position of the centerof the region}$

$\parbox{.30\textwidth}{{\tt (xHalfWidth,yHalfWidth)}}$ 		 : $\parbox{.7\textwidth}{the (x,y) halfwidths of the region - for {\tt elliptannulus}: values for the inner andouter ellipse respectively}$

$\parbox{.30\textwidth}{{\tt (xLoLeft,yLoLeft,}\\ {\tt xUpRight,yUpRight)}}$ 		 : $\parbox{.7\textwidth}{thecoordinates of the lower left and upper right corner of the rectangle}$

$\parbox{.30\textwidth}{{\tt (radius)}}$ 		 : $\parbox{.7\textwidth}{the half the diameter of the circle}$

$\parbox{.30\textwidth}{{\tt (radius1,radius2)}}$ 		 : $\parbox{.7\textwidth}{the inner and outer halfdiameters of the annulus}$

$\parbox{.30\textwidth}{{\tt (fromAngle,toAngle)}}$		 : $\parbox{.7\textwidth}{two angles in decimal degreesdefining a sector; {\tt fromAngle} must be lower than or equal to{\tt toAngle}}$

$\parbox{.30\textwidth}{{\tt (rotation)}}$		 : $\parbox{.7\textwidth}{the angle in decimal degrees that the regionis...
...inner and outer ellipse respectively ({\tt rotationInner},{\tt rotationOuter})}$

$\parbox{.30\textwidth}{{\tt (Xcolumn,Ycolumn)}}$ 		 : $\parbox{.7\textwidth}{the coordinates of the pointto test - usually given as column names}$

Please note:

• Although this is usually the case, the above filter functions do not have to be necessarily applied in the spatial domain. (Xcolumn,Ycolumn) can indeed be the names of any columns in the table, i.e., selections in any two-dimensional data space are possible.
• In the case of the polygon filter the result of the inclusion test for points that lie exactly on a boundary or coincide with a vertex is uncertain. If this behavior is unacceptable please avail the polygon2 filter whose inclusion test results for those points is always positive. This comes at the price of a worse run time efficiency.