# In the explanation of fitgeometry=general of drizzlepac.tweakreg.TweakReg, How are there two different rotation with respect to "x axis" and "y axis"?

While the shift file looks nearly identical to the prior run,
this is because the axis-dependent rotation
and scale values are averaged together in the shiftfile.
To determine the actual values, it is necessary to inspect the logfile.

j9irw5kaq  SCALE_X: 1.000008792  SCALE_Y: 1.00000757  ROT_X: 0.002818152  ROT_Y: 359.998708  SKEW: 359.9958898
j9irw4b1q  SCALE_X: 0.999986877  SCALE_Y: 1.00003072  ROT_X: 0.004877188  ROT_Y: 0.00405990  SKEW:  -0.0008173


The above script is related to the axis explanation of fitgeometry=general of drizzlepac.tweakreg.TweakReg. (and this is from DrizzlePac tutorial)

How are there two different rotation with respect to "x axis" and "y axis"?

In two-dimensional space, there is just one rotation with x-axis and y-axis separately, NOT two rotations.

• Screenshots of text are strongly discouraged in Stack Exchange, especially when you can just copy/paste the actual text. If you add four spaces in the beginning of the line your code-like items will display as a code block (equal spaced font) like this. Thanks!
– uhoh
Aug 6, 2022 at 12:03
• Two possibilities: 1. The ROT_X and ROT_Y values differ by less than the errors, and so are not actually different; 2. A real difference could be an indication of a distortion, which cannot be accurately represented by a uniform rotation. Aug 6, 2022 at 14:30
• @ago Thank you for good comment. I edited it.
– BAO
Aug 7, 2022 at 0:32
• @PeterErwin Thank you, but what's the meaning of uniform rotation of "possibilities 2"? Can we rotate the x-axis and y-axis separately?
– BAO
Aug 7, 2022 at 0:35