3.1 Simplified Region Specification
Any region string representing the union of basic shapes should consist of
the word REGION followed by a number of shape descriptions, see table below.
Here you can find the proper BNF of the language.
Example
Here is the simple example of overlapping circles:
REGION
CIRCLE J2000 180 0 1
CIRCLE J2000 181 0 1
Table of shapes
Convex |
CONVEX J2000 {ra dec D}* |
CONVEX CARTESIAN {x y z D}* |
CONVEX {x y z D}* |
Rectangle |
RECT J2000 {ra dec}2 |
RECT CARTESIAN {x y z }2 |
Circle |
CIRCLE J2000 ra dec R |
CIRCLE CARTESIAN x y z R |
Hull |
CHULL J2000 {ra dec}3+ |
CHULL CARTESIAN {x y z}3+ |
Notation
{...}* 0 or more instances
of the syntax element between the braces
{...}2 exactly 2 instances
of the syntax element between the braces
{...}3+ 3 or more instances
of the syntax element between the braces
R is degrees
in arcminutes.
D is a real number between -1 and 1
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