Custom tracts and patches with LSSTpipe

Support
1

I’m trying to produce coadds from HSC data onto a specific set of tiles used in the CFIS survey. Is there a way to get makeDiscreteSkyMap.py to set up tracts and patches that exactly match an existing image that wasn’t processed with lsstipipe?

2

You should use makeSkyMap.py instead of makeDiscreteSkyMap.py, and use configuration overrides something like the following:

# Configuration for DiscreteSkyMap
# tract=0: M31
config.skyMap["discrete"].raList = [10.7]
config.skyMap["discrete"].decList = [41.3]
config.skyMap["discrete"].radiusList = [0.8]
config.skyMap["discrete"].pixelScale = 0.168
config.skyMap.name = "discrete"

With some care, you can choose the appropriate values to reproduce the WCS in your existing image – assuming it’s a TAN projection. If it’s something much more complicated (e.g., including any distortion), you’re out of luck, and will need to resample that image.

3

There isn’t a way to set CRVAL/CRPIX and so on to specific values?

4

With the current code you can’t just set CRVAL,CRPIX directly (but maybe we could write a subclass that lets you do that).