ginga
ginga copied to clipboard
ejeschke
Feature Request: Draw shape based on iso-flux contours
As requested by Elena Sacchi in Ginga unconference session in JWST Data Analysis Workshop II, it would be nice to draw a shape based on some iso-flux contour.
Note: This might overlap a bit with imexam functionality. Maybe we should wait to see how that imexam plugin works out first (c/c @sosey).
I don't think this overlaps too much, but would need to be implemented in both viewers (ginga and ds9). Are you talking about them hand-selecting anything or figuring out the contours based on some other user input and then just drawing? And by shape do you mean an astropy/region?
I didn't ask for a lot of details. It was just a single-line question asked during the workshop, which is what was recorded above. Naively, I would assume user wants to draw an irregular shape (in Ginga, it would use some kind of Path object, as Ginga has not yet adopted Astropy's region stuff) that follows the selected flux value (maybe +/- certain delta flux). Exactly how that flux is selected (by clicking or entering in a box), I am not sure. I am guessing user would expect something like http://matplotlib.org/examples/pylab_examples/contour_demo.html .
This could also possibly be done with an overlay, similar to the Overlays plugin, but confined to some area around the drawing region.
How does matplotlib represent contours internally? As polygons?
Wondering if you could represent a contour as a compound object made up of filled polygons.
Maybe we can go the lazy route and have such a plugin just overlay matplotlib contours somehow?