regdiff(7) [debian man page]
regdiff(7) SAORD Documentation regdiff(7) NAME
RegDiff - Differences Between Funtools and IRAF Regions SYNOPSIS
Describes the differences between Funtools/ds9 regions and the old IRAF/PROS regions. DESCRIPTION
We have tried to make Funtools regions compatible with their predecessor, IRAF/PROS regions. For simple regions and simple boolean algebra between regions, there should be no difference between the two implementations. The following is a list of differences and incompatibili- ties between the two: o If a pixel is covered by two different regions expressions, Funtools assigns the mask value of the first region that contains that pixel. That is, successive regions do not overwrite previous regions in the mask, as was the case with the original PROS regions. This means that one must define overlapping regions in the reverse order in which they were defined in PROS. If region N is fully con- tained within region M, then N should be defined before M, or else it will be "covered up" by the latter. This change is necessitated by the use of optimized filter compilation, i.e., Funtools only tests individual regions until a proper match is made. o The PANDA region has replaced the old PROS syntax in which a PIE accelerator was combined with an ANNULUS accelerator using AND. That is, ANNULUS(20,20,0,15,n=4) & PIE(20,20,0,360,n=3) has been replaced by: PANDA(20,20,0,360,3,0,15,4) The PROS syntax was inconsistent with the meaning of the AND operator. o The meaning of pure numbers (i.e., without format specifiers) in regions has been clarified, as has the syntax for specifying coordi- nate systems. See the general discussion on Spatial Region Filtering for more information. SEE ALSO
See funtools(7) for a list of Funtools help pages version 1.4.2 January 2, 2008 regdiff(7)
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regalgebra(7) SAORD Documentation regalgebra(7) NAME
RegAlgebra - Boolean Algebra on Spatial Regions SYNOPSIS
This document describes the boolean arithmetic defined for region expressions. DESCRIPTION
When defining a region, several shapes can be combined using boolean operations. The boolean operators are (in order of precedence): Symbol Operator Associativity ------ -------- ------------- ! not right to left & and left to right ^ exclusive or left to right | inclusive or left to right For example, to create a mask consisting of a large circle with a smaller box removed, one can use the and and not opera- tors: CIRCLE(11,11,15) & !BOX(11,11,3,6) and the resulting mask is: 1234567890123456789012345678901234567890 ---------------------------------------- 1:1111111111111111111111.................. 2:1111111111111111111111.................. 3:11111111111111111111111................. 4:111111111111111111111111................ 5:111111111111111111111111................ 6:1111111111111111111111111............... 7:1111111111111111111111111............... 8:1111111111111111111111111............... 9:111111111...1111111111111............... 10:111111111...1111111111111............... 11:111111111...1111111111111............... 12:111111111...1111111111111............... 13:111111111...1111111111111............... 14:111111111...1111111111111............... 15:1111111111111111111111111............... 16:1111111111111111111111111............... 17:111111111111111111111111................ 18:111111111111111111111111................ 19:11111111111111111111111................. 20:1111111111111111111111.................. 21:1111111111111111111111.................. 22:111111111111111111111................... 23:..11111111111111111..................... 24:...111111111111111...................... 25:.....11111111111........................ 26:........................................ 27:........................................ 28:........................................ 29:........................................ 30:........................................ 31:........................................ 32:........................................ 33:........................................ 34:........................................ 35:........................................ 36:........................................ 37:........................................ 38:........................................ 39:........................................ 40:........................................ A three-quarter circle can be defined as: CIRCLE(20,20,10) & !PIE(20,20,270,360) and looks as follows: 1234567890123456789012345678901234567890 ---------------------------------------- 1:........................................ 2:........................................ 3:........................................ 4:........................................ 5:........................................ 6:........................................ 7:........................................ 8:........................................ 9:........................................ 10:........................................ 11:...............111111111................ 12:..............11111111111............... 13:............111111111111111............. 14:............111111111111111............. 15:...........11111111111111111............ 16:..........1111111111111111111........... 17:..........1111111111111111111........... 18:..........1111111111111111111........... 19:..........1111111111111111111........... 20:..........1111111111111111111........... 21:..........1111111111.................... 22:..........1111111111.................... 23:..........1111111111.................... 24:..........1111111111.................... 25:...........111111111.................... 26:............11111111.................... 27:............11111111.................... 28:..............111111.................... 29:...............11111.................... 30:........................................ 31:........................................ 32:........................................ 33:........................................ 34:........................................ 35:........................................ 36:........................................ 37:........................................ 38:........................................ 39:........................................ 40:........................................ Two non-intersecting ellipses can be made into the same region: ELL(20,20,10,20,90) | ELL(1,1,20,10,0) and looks as follows: 1234567890123456789012345678901234567890 ---------------------------------------- 1:11111111111111111111.................... 2:11111111111111111111.................... 3:11111111111111111111.................... 4:11111111111111111111.................... 5:1111111111111111111..................... 6:111111111111111111...................... 7:1111111111111111........................ 8:111111111111111......................... 9:111111111111............................ 10:111111111............................... 11:...........11111111111111111............ 12:........111111111111111111111111........ 13:.....11111111111111111111111111111...... 14:....11111111111111111111111111111111.... 15:..11111111111111111111111111111111111... 16:.1111111111111111111111111111111111111.. 17:111111111111111111111111111111111111111. 18:111111111111111111111111111111111111111. 19:111111111111111111111111111111111111111. 20:111111111111111111111111111111111111111. 21:111111111111111111111111111111111111111. 22:111111111111111111111111111111111111111. 23:111111111111111111111111111111111111111. 24:.1111111111111111111111111111111111111.. 25:..11111111111111111111111111111111111... 26:...11111111111111111111111111111111..... 27:.....11111111111111111111111111111...... 28:.......111111111111111111111111......... 29:...........11111111111111111............ 30:........................................ 31:........................................ 32:........................................ 33:........................................ 34:........................................ 35:........................................ 36:........................................ 37:........................................ 38:........................................ 39:........................................ 40:........................................ You can use several boolean operations in a single region expression, to create arbitrarily complex regions. With the important exception below, you can apply the operators in any order, using parentheses if necessary to override the natural precedences of the operators. NB: Using a panda shape is always much more efficient than explicitly specifying "pie & annulus", due to the ability of panda to place a limit on the number of pixels checked in the pie shape. If you are going to specify the intersection of pie and annulus, use panda instead. As described in "help regreometry", the PIE slice goes to the edge of the field. To limit its scope, PIE usually is is combined with other shapes, such as circles and annuli, using boolean operations. In this context, it is worth noting that that there is a difference between -PIE and &!PIE. The former is a global exclude of all pixels in the PIE slice, while the latter is a local excludes of pixels affecting only the region(s) with which the PIE is combined. For example, the following region uses &!PIE as a local exclude of a single circle. Two other circles are also defined and are unaffected by the local exclude: CIRCLE(1,8,1) CIRCLE(8,8,7)&!PIE(8,8,60,120)&!PIE(8,8,240,300) CIRCLE(15,8,2) 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 - - - - - - - - - - - - - - - 15: . . . . . . . . . . . . . . . 14: . . . . 2 2 2 2 2 2 2 . . . . 13: . . . 2 2 2 2 2 2 2 2 2 . . . 12: . . 2 2 2 2 2 2 2 2 2 2 2 . . 11: . . 2 2 2 2 2 2 2 2 2 2 2 . . 10: . . . . 2 2 2 2 2 2 2 . . . . 9: . . . . . . 2 2 2 . . . . 3 3 8: 1 . . . . . . . . . . . . 3 3 7: . . . . . . 2 2 2 . . . . 3 3 6: . . . . 2 2 2 2 2 2 2 . . . . 5: . . 2 2 2 2 2 2 2 2 2 2 2 . . 4: . . 2 2 2 2 2 2 2 2 2 2 2 . . 3: . . . 2 2 2 2 2 2 2 2 2 . . . 2: . . . . 2 2 2 2 2 2 2 . . . . 1: . . . . . . . . . . . . . . . Note that the two other regions are not affected by the &!PIE, which only affects the circle with which it is combined. On the other hand, a -PIE is an global exclude that does affect other regions with which it overlaps: CIRCLE(1,8,1) CIRCLE(8,8,7) -PIE(8,8,60,120) -PIE(8,8,240,300) CIRCLE(15,8,2) 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 - - - - - - - - - - - - - - - 15: . . . . . . . . . . . . . . . 14: . . . . 2 2 2 2 2 2 2 . . . . 13: . . . 2 2 2 2 2 2 2 2 2 . . . 12: . . 2 2 2 2 2 2 2 2 2 2 2 . . 11: . . 2 2 2 2 2 2 2 2 2 2 2 . . 10: . . . . 2 2 2 2 2 2 2 . . . . 9: . . . . . . 2 2 2 . . . . . . 8: . . . . . . . . . . . . . . . 7: . . . . . . 2 2 2 . . . . . . 6: . . . . 2 2 2 2 2 2 2 . . . . 5: . . 2 2 2 2 2 2 2 2 2 2 2 . . 4: . . 2 2 2 2 2 2 2 2 2 2 2 . . 3: . . . 2 2 2 2 2 2 2 2 2 . . . 2: . . . . 2 2 2 2 2 2 2 . . . . 1: . . . . . . . . . . . . . . . The two smaller circles are entirely contained within the two exclude PIE slices and therefore are excluded from the region. SEE ALSO
See funtools(7) for a list of Funtools help pages version 1.4.2 January 2, 2008 regalgebra(7)