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Diffstat (limited to 'doc/source')
| -rw-r--r-- | doc/source/user.rst | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/doc/source/user.rst b/doc/source/user.rst index 60b77d8..40dff39 100644 --- a/doc/source/user.rst +++ b/doc/source/user.rst @@ -192,10 +192,14 @@ What is a skyline member? Each member in `~sphere.skyline.SkyLine.members` belongs to the `~sphere.skyline.SkyLineMember` class, which contains image name (with path if -given), science extension, and WCS object and polygon of that extension. +given), science extension(s), and composite WCS and polygon of the extension(s). +All skylines start out with a single member from a single image. When operations +are used to find composite or intersecting skylines, the resulting skyline can +have multiple members. -For example, an ACS/WFC full-frame image would give 2 members, one from EXT 1 -and another from EXT 4. +For example, a skyline from an ACS/WFC full-frame image would give 1 member, +which is a composite of extensions 1 and 4. A skyline from the union of 2 such +images would have 2 members, and so forth. Creating skylines ````````````````` @@ -224,7 +228,8 @@ following (which are still accessible indirectly via In addition, `~sphere.skyline.SkyLine` also has these operations available: - `~sphere.skyline.SkyLine.to_wcs`: Return a composite HST WCS object defined - by all the members. + by all the members. In a skyline resulting from intersection, this does + *not* return the WCS of the intersecting polygons. - `~sphere.skyline.SkyLine.add_image`: Return a new skyline that is the union of two skylines. This should be used, *not* `SkyLine.union` (which is |