Versions Compared

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.


Use case

 

(Updated Aug 2017 with Aladin v9.6, SE)

Use This starts with a use case by Sébastien Derrière, CDS (June 2015), enlarged with comments and implementation notes

Stéphane Erard comments are introduced by >


Summary : Build a 3D spherical HiPS off Io, and overplot surface features from USG catalogue.Summary : it is possible to convert planetary or satellite
to HiPS, in order to visualize them in Aladin, explore the
surface feature, and even overlay catalogues of features.
Introduction :
This is an extension of Use Case #28 of Aladin Beta Test page (requires Aladin v9 and up):
http://aladin.u-strasbg.fr/java/Demo/AladinDemo.gml    > Use of Aladin 8 beta version (link on that page) is required - should now also work with Aladin 9gm


Step-by-step:
Retrieve image of planetary mapPlanetary maps are available, for example from here:
http://laps.noaa.gov/albers/sos/
or here
ftp://pdsimage2.wr.usgs.gov/pub/pigpen/
As
In this example, we work with Io:
ftp://pdsimage2.wr.usgs.gov/pub/pigpen/io/io_global_images.zip

• extract io_bjj_0dd.tif, convert to jpg

In the terminal, type:
    > convert io_bjj_0dd.tif io_bjj_0dd.jpg
    (in the terminal)

• Load jpg image in Aladin as local file.
Image size is 2880 x 1440
Set Frame drop menu (next to Location field) to Planet

• Apply astrometric solution:
Image > Astrometrical calibration
Use parameters:
Central pixel 1440.0 720.0, with pix ang size
Pixel angular size = 7.5' and projection CARTESIAN(= 360/2880*60)
Projection = CARTESIAN
Rotation = 0°
RA symmetry: False

• Convert to HiPS :
Tool > Convert current image to a HiPS
Apply grid, pan around, zoom in/out ...
    > Type Comm-G to overplot coordinate grid
    > Beware that  longitudes are handled as Righ Ascensions (inverted)


• Adding catalogue:
Planetary nomenclature downloaded from
ftp://pdsimage2.wr.usgs.gov/pub/pigpen/nomenclature/nomenclature_all_feb2004.zip
Extract nomenclature_all_feb2004.dbf
convert to csv with http://dbfconv.com/

Little cleanup of csv file, and load it in TOPCAT.
    > Remove EOL character <NULL> in TextMate or another handy editor


• Filter Io features only by creating subset (io, expression SA=="io")
-> 221 lines out of 8395 in io subset
    > Click on red/violet icon, add a filter
    & "plot subset" io in main window

Choose io Row subset in main TOPCAT window and broadcast to Aladin via SAMP

• Right-click catalogue plane in Aladin, Column Information
Click on Coord for LATITUDE and LONG360, pretending they are DEC and RA, respectively.

• Create dedicated filter :
In advanced mode, use the following expression :
    > this is Catalogue menu item / create new filter / advanced mode

{
# scale is 113.3 arcsec/km
draw ellipse(113.3*${DIAM}, 113.3*${DIAM}, 0) rainbow(${AD},1979,2003)
draw ${NAME} rainbow(${AD},1979,2003)
}
Displays names and sizes of surface features, color-coded by year of discovery.

• Remaining issues :
Defaut orientation of RA or longitudes in Aladin is different
from the one used in planetary science, therefore the surface
is viewed as from within the planetary body, not from outside.



> Other pb on my side :
- long180GIS does not work either?  

...