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From previous ObsParis / CDS meeting
Using Aladin prototype v10 v9.6 (627/6/2017) and TOPCAT v4.4 on MacOS
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HiPS (Hierarchical progressive survey) are associations of healpix maps at different scales. They provide efficient multiresolution scaling on the fly in Aladin.
1)
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From a single file (updated Aug 2017)
The use is mostly to get a 3D spherical model from a map, where contours and objects can be overplotted. See Io use case for more details: Aladin & planetary surfaces
In AlLoad Aladin, load file Mars_MGS_colorhillshade_mola_1024.jpg (MOLA integrated relief map)
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Tool > Convert current image to a HiPS
• The hpx image should be is saved (somewhere) on disk automatically
ProblemOpen issue: this provides a correct E longitude frame. However, s_region footprints sent from an EPN-TAP service will now plot at the wrong longitude (see figure below)
E.g. for Huygens crater, s_region = Polygon UNKNOWNFrame 55.582 -17.8305918846 54.7737623408 -17.7532983656… 7532983656…
(in short, s_region Unknown frame is incorrectly assumed W-handed)
2) From a series of local files in Aladin
This method will provide adaptive resolution when using files of various scales
TBC, does did not work on my machine early 2017.
MOC use case in Aladin
MOC (Multi-Order Coverages) are footprints defined in terms of healpix cells list mixing various resolutions. They provide immediate location information e.g. about intersections.
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